Python容器转换与共有函数举例详解

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  • 目录
    • Python容器转换与共有函数详解
      • 一、容器类型概览
      • 二、容器类型转换
        • 1. 基本容器转换
        • 2. 高级转换示例
        • 3. 实际应用场景
      • 三、容器共有函数
        • 1. 通用操作函数
        • 2. 成员测试和迭代
        • 3. 切片操作(适用于序列类型)
        • 4. 容器比较和复制
        • 5. 内置函数与容器操作
      • 四、综合应用示例
        • 五、性能考虑与最佳实践
          • 总结
            • 容器转换要点:
            • 容器共有函数要点:
            • 性能建议:
        • 现代C++容器转换与共有函数详解
          • 一、C++ STL容器概览
            • 二、容器转换
              • 1. 使用构造函数进行转换
              • 2. 使用赋值和交换
              • 3. 使用算法进行转换
            • 三、容器共有函数
              • 1. 通用成员函数
              • 2. 序列容器特有操作
              • 3. 关联容器特有操作
              • 4. 容器适配器特有操作
            • 四、实用工具函数
              • 1. 迭代器工具
              • 2. 算法库中的容器操作
              • 3. 视图和范围(C++20)
            • 五、类型转换和类型特性
              • 1. 类型转换工具
              • 2. 智能指针与容器
            • 六、性能优化技巧
              • 1. 高效容器操作
              • 2. 内存池和自定义分配器
            • 七、综合示例:学生成绩管理系统
              • 总结对比表
                • 最佳实践
                • 总结

                  Python主要的内置容器类型:

                  容器类型 描述 可变性 是否有序 示例
                  列表(list) 有序的元素集合 可变 有序 [1, 2, 3]
                  元组(tuple) 不可变的元素集合 不可变 有序 (1, 2, 3)
                  集合(set) 无序的唯一元素集合 可变 无序 {1, 2, 3}
                  冻结集合(frozenset) 不可变的集合 不可变 无序 frozenset([1, 2, 3])
                  字典(dict) 键值对映射 可变 Python 3.7+有序 {'a': 1, 'b': 2}
                  字符串(str) 字符序列 不可变 有序 "hello"
                  字节(bytes) 字节序列 不可变 有序 b"hello"
                  字节数组(bytearray) 可变的字节序列 可变 有序 bytearray(b"hello")

                  # ==================== 基本容器转换 ====================
                  
                  # 1. 列表与其他容器的转换
                  original_list = [1, 2, 3, 2, 1]  # 包含重复元素
                  
                  # 列表 -> 元组
                  list_to_tuple = tuple(original_list)
                  print(f"列表转元组: {original_list} -> {list_to_tuple}")
                  print(f"类型: {type(list_to_tuple)}")
                  
                  # 列表 -> 集合(自动去重)
                  list_to_set = set(original_list)
                  print(f"列表转集合: {original_list} -> {list_to_set}")
                  print(f"类型: {type(list_to_set)}")
                  
                  # 列表 -> 冻结集合
                  list_to_frozenset = frozenset(original_list)
                  print(f"列表转冻结集合: {original_list} -> {list_to_frozenset}")
                  print(f"类型: {type(list_to_frozenset)}")
                  
                  print("n" + "="*50 + "n")
                  
                  # 2. 元组与其他容器的转换
                  original_tuple = (1, 2, 3, 2, 1)
                  
                  # 元组 -> 列表
                  tuple_to_list = list(original_tuple)
                  print(f"元组转列表: {original_tuple} -> {tuple_to_list}")
                  
                  # 元组 -> 集合
                  tuple_to_set = set(original_tuple)
                  print(f"元组转集合: {original_tuple} -> {tuple_to_set}")
                  
                  # 元组 -> 冻结集合
                  tuple_to_frozenset = frozenset(original_tuple)
                  print(f"元组转冻结集合: {original_tuple} -> {tuple_to_frozenset}")
                  
                  print("n" + "="*50 + "n")
                  
                  # 3. 集合与其他容器的转换
                  original_set = {1, 2, 3, 4, 5}
                  
                  # 集合 -> 列表(无序,可能顺序不同)
                  set_to_list = list(original_set)
                  print(f"集合转列表: {original_set} -> {set_to_list}")
                  
                  # 集合 -> 元组
                  set_to_tuple = tuple(original_set)
                  print(f"集合转元组: {original_set} -> {set_to_tuple}")
                  
                  # 集合 -> 冻结集合
                  set_to_frozenset = frozenset(original_set)
                  print(f"集合转冻结集合: {original_set} -> {set_to_frozenset}")
                  
                  print("n" + "="*50 + "n")
                  
                  # 4. 字符串与容器的转换
                  text = "hello world"
                  
                  # 字符串 -> 列表(字符列表)
                  str_to_list = list(text)
                  print(f"字符串转列表: '{text}' -> {str_to_list}")
                  
                  # 字符串 -> 元组
                  str_to_tuple = tuple(text)
                  print(f"字符串转元组: '{text}' -> {str_to_tuple}")
                  
                  # 字符串 -> 集合(唯一字符)
                  str_to_set = set(text)
                  print(f"字符串转集合: '{text}' -> {str_to_set}")
                  
                  # 列表 -> 字符串(join方法)
                  list_to_str = ''.join(['h', 'e', 'l', 'l', 'o'])
                  print(f"字符列表转字符串: {['h', 'e', 'l', 'l', 'o']} -> '{list_to_str}'")
                  
                  # 单词列表转字符串
                  words = ['hello', 'world', 'python']
                  words_to_str = ' '.join(words)
                  print(f"单词列表转字符串: {words} -> '{words_to_str}'")
                  
                  print("n" + "="*50 + "n")
                  
                  # 5. 字典与其他容器的转换
                  original_dict = {'a': 1, 'b': 2, 'c': 3}
                  
                  # 字典 -> 列表(只保留键)
                  dict_keys_to_list = list(original_dict)
                  print(f"字典转列表(键): {original_dict} -> {dict_keys_to_list}")
                  
                  # 字典 -> 列表(键列表)
                  dict_keys_list = list(original_dict.keys())
                  print(f"字典键转列表: {original_dict} -> {dict_keys_list}")
                  
                  # 字典 -> 列表(值列表)
                  dict_values_list = list(original_dict.values())
                  print(f"字典值转列表: {original_dict} -> {dict_values_list}")
                  
                  # 字典 -> 列表(键值对列表)
                  dict_items_list = list(original_dict.items())
                  print(f"字典项转列表: {original_dict} -> {dict_items_list}")
                  
                  # 字典 -> 元组(键的元组)
                  dict_keys_tuple = tuple(original_dict)
                  print(f"字典键转元组: {original_dict} -> {dict_keys_tuple}")
                  
                  # 字典 -> 集合(键的集合)
                  dict_keys_set = set(original_dict)
                  print(f"字典键转集合: {original_dict} -> {dict_keys_set}")
                  
                  print("n" + "="*50 + "n")
                  
                  # 6. 列表/元组 -> 字典(特殊转换)
                  # 使用zip将两个列表转换为字典
                  keys = ['a', 'b', 'c']
                  values = [1, 2, 3]
                  list_to_dict = dict(zip(keys, values))
                  print(f"两个列表转字典: keys={keys}, values={values} -> {list_to_dict}")
                  
                  # 列表/元组的元组/列表 -> 字典
                  pairs = [('a', 1), ('b', 2), ('c', 3)]
                  pairs_to_dict = dict(pairs)
                  print(f"对列表转字典: {pairs} -> {pairs_to_dict}")
                  
                  # 嵌套列表转字典
                  nested_list = [['x', 10], ['y', 20], ['z', 30]]
                  nested_to_dict = dict(nested_list)
                  print(f"嵌套列表转字典: {nested_list} -> {nested_to_dict}")
                  

                  # ==================== 高级转换技巧 ====================
                  
                  def advanced_conversions():
                      print("高级转换技巧示例:")
                      
                      # 1. 使用推导式进行转换
                      numbers = [1, 2, 3, 4, 5]
                      
                      # 列表推导式转换
                      squares = [x**2 for x in numbers]
                      print(f"数字平方列表: {numbers} -> {squares}")
                      
                      # 字典推导式转换
                      square_dict = {x: x**2 for x in numbers}
                      print(f"数字平方字典: {numbers} -> {square_dict}")
                      
                      # 集合推导式转换
                      square_set = {x**2 for x in numbers}
                      print(f"数字平方集合: {numbers} -> {square_set}")
                      
                      # 2. 使用map函数转换
                      numbers_str = list(map(str, numbers))
                      print(f"数字转字符串列表: {numbers} -> {numbers_str}")
                      
                      # 3. 使用filter过滤转换
                      even_numbers = list(filter(lambda x: x % 2 == 0, numbers))
                      print(f"过滤偶数: {numbers} -> {even_numbers}")
                      
                      # 4. 嵌套容器转换
                      nested_list = [[1, 2], [3, 4], [5, 6]]
                      
                      # 展平嵌套列表
                      flat_list = [item for sublist in nested_list for item in sublist]
                      print(f"展平嵌套列表: {nested_list} -> {flat_list}")
                      
                      # 5. 多重转换
                      data = [(1, 'a'), (2, 'b'), (3, 'c')]
                      
                      # 转换为字典
                      tuple_list_to_dict = dict(data)
                      print(f"元组列表转字典: {data} -> {tuple_list_to_dict}")
                      
                      # 转换为两个列表
                      nums, letters = zip(*data) if data else ([], [])
                      print(f"元组列表拆分为两个列表: {data} -> nums={nums}, letters={letters}")
                      
                      # 6. 自定义对象转换
                      class Person:
                          def __init__(self, name, age):
                              self.name = name
                              self.age = age
                          
                          def __repr__(self):
                              return f"Person(name={self.name}, age={self.age})"
                      
                      people = [Person("Alice", 25), Person("Bob", 30), Person("Charlie", 35)]
                      
                      # 对象列表转换为名字列表
                      names = [person.name for person in people]
                      print(f"对象列表转名字列表: {people} -> {names}")
                      
                      # 对象列表转换为字典
                      people_dict = {person.name: person.age for person in people}
                      print(f"对象列表转字典: {people} -> {people_dict}")
                  
                  advanced_conversions()
                  

                  # ==================== 实际应用场景 ====================
                  
                  def practical_applications():
                      print("n实际应用场景:")
                      
                      # 场景1: 数据清洗和去重
                      print("场景1: 数据清洗和去重")
                      raw_data = [5, 2, 8, 2, 5, 9, 1, 5, 8]
                      
                      # 使用集合去重,然后排序
                      cleaned_data = sorted(set(raw_data))
                      print(f"原始数据: {raw_data}")
                      print(f"清洗后数据: {cleaned_data}")
                      
                      # 场景2: 统计词频
                      print("n场景2: 统计词频")
                      text = "apple banana apple orange banana apple"
                      words = text.split()
                      
                      # 多种方法统计词频
                      # 方法1: 使用字典
                      word_count = {}
                      for word in words:
                          word_count[word] = word_count.get(word, 0) + 1
                      print(f"方法1 - 字典统计: {word_count}")
                      
                      # 方法2: 使用collections.Counter
                      from collections import Counter
                      word_counter = Counter(words)
                      print(f"方法2 - Counter统计: {dict(word_counter)}")
                      
                      # 场景3: 矩阵转置
                      print("n场景3: 矩阵转置")
                      matrix = [
                          [1, 2, 3],
                          [4, 5, 6],
                          [7, 8, 9]
                      ]
                      
                      # 使用zip转置
                      transposed = list(zip(*matrix))
                      print(f"原始矩阵: {matrix}")
                      print(f"转置矩阵: {transposed}")
                      
                      # 场景4: 分组数据
                      print("n场景4: 分组数据")
                      students = [
                          ("Alice", "Math", 85),
                          ("Bob", "Math", 90),
                          ("Alice", "Science", 92),
                          ("Bob", "Science", 88),
                          ("Charlie", "Math", 78)
                      ]
                      
                      # 按学生分组成绩
                      from collections import defaultdict
                      student_grades = defaultdict(list)
                      
                      for name, subject, grade in students:
                          student_grades[name].append((subject, grade))
                      
                      print("按学生分组成绩:")
                      for student, grades in student_grades.items():
                          print(f"  {student}: {grades}")
                      
                      # 场景5: 配置文件解析
                      print("n场景5: 配置文件解析")
                      config_lines = [
                          "DATABASE_HOST=localhost",
                          "DATABASE_PORT=5432",
                          "DATABASE_NAME=mydb",
                          "DEBUG=true"
                      ]
                      
                      # 转换为配置字典
                      config_dict = {}
                      for line in config_lines:
                          if '=' in line:
                              key, value = line.split('=', 1)
                              config_dict[key] = value
                      
                      print(f"配置字典: {config_dict}")
                      
                      # 场景6: 处理CSV数据
                      print("n场景6: 处理CSV数据")
                      csv_data = "name,age,citynAlice,25,New YorknBob,30,LondonnCharlie,35,Paris"
                      
                      # 解析CSV为列表字典
                      lines = csv_data.split('n')
                      headers = lines[0].split(',')
                      records = []
                      
                      for line in lines[1:]:
                          values = line.split(',')
                          record = dict(zip(headers, values))
                          records.append(record)
                      
                      print("解析后的数据:")
                      for record in records:
                          print(f"  {record}")
                  
                  practical_applications()
                  

                  # ==================== 容器共有函数 ====================
                  
                  def common_container_functions():
                      print("容器共有函数示例:")
                      
                      # 示例数据
                      sample_list = [1, 2, 3, 4, 5]
                      sample_tuple = (1, 2, 3, 4, 5)
                      sample_set = {1, 2, 3, 4, 5}
                      sample_dict = {'a': 1, 'b': 2, 'c': 3}
                      sample_string = "hello"
                      
                      # 1. len() - 获取容器长度
                      print("n1. len() - 获取容器长度:")
                      print(f"列表长度: len({sample_list}) = {len(sample_list)}")
                      print(f"元组长度: len({sample_tuple}) = {len(sample_tuple)}")
                      print(f"集合长度: len({sample_set}) = {len(sample_set)}")
                      print(f"字典长度: len({sample_dict}) = {len(sample_dict)}")
                      print(f"字符串长度: len('{sample_string}') = {len(sample_string)}")
                      
                      # 2. max() - 获取最大值
                      print("n2. max() - 获取最大值:")
                      print(f"列表最大值: max({sample_list}) = {max(sample_list)}")
                      print(f"元组最大值: max({sample_tuple}) = {max(sample_tuple)}")
                      print(f"集合最大值: max({sample_set}) = {max(sample_set)}")
                      
                      # 字典最大值(默认比较键)
                      print(f"字典键最大值: max({sample_dict}) = {max(sample_dict)}")
                      print(f"字典值最大值: max({sample_dict}.values()) = {max(sample_dict.values())}")
                      
                      # 3. min() - 获取最小值
                      print("n3. min() - 获取最小值:")
                      print(f"列表最小值: min({sample_list}) = {min(sample_list)}")
                      print(f"元组最小值: min({sample_tuple}) = {min(sample_tuple)}")
                      print(f"集合最小值: min({sample_set}) = {min(sample_set)}")
                      
                      # 4. sum() - 求和(仅限数值容器)
                      print("n4. sum() - 求和:")
                      print(f"列表求和: sum({sample_list}) = {sum(sample_list)}")
                      print(f"元组求和: sum({sample_tuple}) = {sum(sample_tuple)}")
                      print(f"集合求和: sum({sample_set}) = {sum(sample_set)}")
                      
                      # 字典值求和
                      print(f"字典值求和: sum({sample_dict}.values()) = {sum(sample_dict.values())}")
                      
                      # 5. any() - 任意元素为真则返回True
                      print("n5. any() - 任意元素为真:")
                      test_list = [0, False, '', None]
                      print(f"any({test_list}) = {any(test_list)}")
                      
                      test_list2 = [0, False, 1, '']
                      print(f"any({test_list2}) = {any(test_list2)}")
                      
                      # 6. all() - 所有元素为真则返回True
                      print("n6. all() - 所有元素为真:")
                      print(f"all({test_list}) = {all(test_list)}")
                      print(f"all({sample_list}) = {all(sample_list)}")
                      
                      # 7. sorted() - 排序(返回新列表)
                      print("n7. sorted() - 排序:")
                      unsorted_list = [3, 1, 4, 1, 5, 9, 2]
                      print(f"排序前: {unsorted_list}")
                      print(f"升序排序: {sorted(unsorted_list)}")
                      print(f"降序排序: {sorted(unsorted_list, reverse=True)}")
                      
                      # 字典排序
                      print(f"字典按键排序: {sorted(sample_dict)}")
                      print(f"字典按值排序: {sorted(sample_dict.items(), key=lambda x: x[1])}")
                      
                      # 8. reversed() - 反转(返回迭代器)
                      print("n8. reversed() - 反转:")
                      print(f"列表反转: {list(reversed(sample_list))}")
                      print(f"元组反转: {tuple(reversed(sample_tuple))}")
                      print(f"字符串反转: {''.join(reversed(sample_string))}")
                      
                      # 9. enumerate() - 同时获取索引和值
                      print("n9. enumerate() - 枚举:")
                      print("列表枚举:")
                      for index, value in enumerate(sample_list):
                          print(f"  [{index}] = {value}")
                      
                      print("字典枚举(键值对):")
                      for index, (key, value) in enumerate(sample_dict.items()):
                          print(f"  [{index}] {key} = {value}")
                      
                      # 10. zip() - 并行迭代多个容器
                      print("n10. zip() - 并行迭代:")
                      names = ["Alice", "Bob", "Charlie"]
                      ages = [25, 30, 35]
                      cities = ["New York", "London", "Paris"]
                      
                      print("并行迭代多个列表:")
                      for name, age, city in zip(names, ages, cities):
                          print(f"  {name} ({age}岁) 来自 {city}")
                      
                      # 转换为字典
                      people_dict = dict(zip(names, ages))
                      print(f"通过zip创建字典: {people_dict}")
                  
                  common_container_functions()
                  

                  # ==================== 成员测试和迭代 ====================
                  
                  def membership_and_iteration():
                      print("n成员测试和迭代:")
                      
                      # 示例数据
                      fruits = ["apple", "banana", "orange", "grape"]
                      fruit_set = {"apple", "banana", "orange", "grape"}
                      fruit_dict = {"apple": 1, "banana": 2, "orange": 3, "grape": 4}
                      
                      # 1. in 操作符 - 成员测试
                      print("1. in 操作符 - 成员测试:")
                      
                      # 列表成员测试
                      print(f"'apple' 在列表 {fruits} 中: {'apple' in fruits}")
                      print(f"'pear' 在列表 {fruits} 中: {'pear' in fruits}")
                      
                      # 集合成员测试(更快)
                      print(f"'apple' 在集合 {fruit_set} 中: {'apple' in fruit_set}")
                      
                      # 字典成员测试(默认测试键)
                      print(f"'apple' 在字典 {fruit_dict} 的键中: {'apple' in fruit_dict}")
                      print(f"1 在字典 {fruit_dict} 的值中: {1 in fruit_dict.values()}")
                      print(f"('apple', 1) 在字典 {fruit_dict} 的项中: {('apple', 1) in fruit_dict.items()}")
                      
                      # 2. not in 操作符
                      print("n2. not in 操作符:")
                      print(f"'pear' 不在列表 {fruits} 中: {'pear' not in fruits}")
                      
                      # 3. 迭代容器
                      print("n3. 迭代容器:")
                      
                      # 列表迭代
                      print("迭代列表:")
                      for fruit in fruits:
                          print(f"  - {fruit}")
                      
                      # 集合迭代(无序)
                      print("n迭代集合:")
                      for fruit in fruit_set:
                          print(f"  - {fruit}")
                      
                      # 字典迭代
                      print("n迭代字典(键):")
                      for key in fruit_dict:
                          print(f"  - {key}")
                      
                      print("n迭代字典(键值对):")
                      for key, value in fruit_dict.items():
                          print(f"  - {key}: {value}")
                      
                      # 4. 带索引的迭代
                      print("n4. 带索引的迭代:")
                      print("使用enumerate:")
                      for i, fruit in enumerate(fruits):
                          print(f"  [{i}] {fruit}")
                      
                      # 5. 同时迭代多个容器
                      print("n5. 同时迭代多个容器:")
                      quantities = [10, 20, 15, 25]
                      prices = [1.5, 0.8, 2.0, 3.5]
                      
                      print("水果库存:")
                      for fruit, qty, price in zip(fruits, quantities, prices):
                          total = qty * price
                          print(f"  {fruit}: {qty}个 × ${price} = ${total:.2f}")
                      
                      # 6. 使用iter()和next()手动迭代
                      print("n6. 手动迭代:")
                      fruit_iter = iter(fruits)
                      print(f"第一次next: {next(fruit_iter)}")
                      print(f"第二次next: {next(fruit_iter)}")
                      print(f"第三次next: {next(fruit_iter)}")
                      
                      # 7. 迭代时修改容器(注意事项)
                      print("n7. 迭代时修改容器(注意事项):")
                      
                      # 错误示例:迭代时删除元素
                      numbers = [1, 2, 3, 4, 5]
                      print(f"原始列表: {numbers}")
                      
                      # 安全的方式:创建副本或使用列表推导式
                      numbers_copy = numbers.copy()
                      to_remove = []
                      
                      for num in numbers_copy:
                          if num % 2 == 0:
                              to_remove.append(num)
                      
                      for num in to_remove:
                          numbers.remove(num)
                      
                      print(f"删除偶数后: {numbers}")
                      
                      # 使用列表推导式(更简洁)
                      numbers = [1, 2, 3, 4, 5]
                      numbers = [num for num in numbers if num % 2 != 0]
                      print(f"使用推导式删除偶数后: {numbers}")
                  
                  membership_and_iteration()
                  

                  # ==================== 切片操作 ====================
                  
                  def slicing_operations():
                      print("n切片操作(适用于序列类型):")
                      
                      # 示例数据
                      data = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
                      text = "Hello, World!"
                      
                      # 基本切片语法: sequence[start:stop:step]
                      
                      # 1. 基本切片
                      print("1. 基本切片:")
                      print(f"完整序列: {data}")
                      print(f"data[2:6]: {data[2:6]}")      # 从索引2到5(不包含6)
                      print(f"data[:5]: {data[:5]}")        # 从开始到索引4
                      print(f"data[5:]: {data[5:]}")        # 从索引5到结束
                      print(f"data[:]: {data[:]}")          # 完整副本
                      
                      # 2. 带步长的切片
                      print("n2. 带步长的切片:")
                      print(f"data[::2]: {data[::2]}")      # 每隔一个元素
                      print(f"data[1::2]: {data[1::2]}")    # 从索引1开始,每隔一个
                      print(f"data[2:8:2]: {data[2:8:2]}")  # 从2到7,每隔一个
                      
                      # 3. 负索引切片
                      print("n3. 负索引切片:")
                      print(f"data[-3:]: {data[-3:]}")      # 最后3个元素
                      print(f"data[:-3]: {data[:-3]}")      # 除了最后3个
                      print(f"data[-5:-2]: {data[-5:-2]}")  # 从倒数第5到倒数第3
                      
                      # 4. 负步长(反转)
                      print("n4. 负步长(反转):")
                      print(f"data[::-1]: {data[::-1]}")    # 反转列表
                      print(f"data[5:1:-1]: {data[5:1:-1]}") # 从索引5到索引2(反向)
                      print(f"data[-2:-6:-1]: {data[-2:-6:-1]}") # 从倒数第2到倒数第5(反向)
                      
                      # 5. 字符串切片
                      print("n5. 字符串切片:")
                      print(f"原始字符串: '{text}'")
                      print(f"text[0:5]: '{text[0:5]}'")    # Hello
                      print(f"text[7:12]: '{text[7:12]}'")  # World
                      print(f"text[::2]: '{text[::2]}'")    # 每隔一个字符
                      print(f"text[::-1]: '{text[::-1]}'")  # 反转字符串
                      
                      # 6. 元组切片
                      print("n6. 元组切片:")
                      data_tuple = tuple(data)
                      print(f"元组切片 data_tuple[2:6]: {data_tuple[2:6]}")
                      
                      # 7. 切片赋值(仅可变序列)
                      print("n7. 切片赋值(仅可变序列):")
                      numbers = [0, 1, 2, 3, 4, 5]
                      print(f"原始列表: {numbers}")
                      
                      # 替换切片部分
                      numbers[2:4] = [20, 30, 40]  # 可以改变元素数量
                      print(f"替换后: {numbers}")
                      
                      # 删除切片部分
                      numbers[1:4] = []
                      print(f"删除后: {numbers}")
                      
                      # 插入元素
                      numbers[2:2] = [100, 200]  # 在索引2处插入
                      print(f"插入后: {numbers}")
                      
                      # 8. 高级切片应用
                      print("n8. 高级切片应用:")
                      
                      # 提取每行数据的特定列
                      matrix = [
                          [1, 2, 3, 4],
                          [5, 6, 7, 8],
                          [9, 10, 11, 12]
                      ]
                      
                      # 提取第二列
                      col2 = [row[1] for row in matrix]
                      print(f"矩阵第二列: {col2}")
                      
                      # 使用切片获取子矩阵
                      submatrix = [row[1:3] for row in matrix[1:3]]
                      print(f"子矩阵: {submatrix}")
                      
                      # 9. 自定义可切片对象
                      print("n9. 自定义可切片对象:")
                      
                      class SliceableList:
                          def __init__(self, data):
                              self.data = list(data)
                          
                          def __getitem__(self, key):
                              if isinstance(key, slice):
                                  # 处理切片
                                  return self.data[key]
                              else:
                                  # 处理单个索引
                                  return self.data[key]
                          
                          def __setitem__(self, key, value):
                              if isinstance(key, slice):
                                  self.data[key] = value
                              else:
                                  self.data[key] = value
                          
                          def __repr__(self):
                              return f"SliceableList({self.data})"
                      
                      custom_list = SliceableList(range(10))
                      print(f"自定义列表: {custom_list}")
                      print(f"自定义列表切片[2:7:2]: {custom_list[2:7:2]}")
                  
                  slicing_operations()
                  

                  # ==================== 容器比较和复制 ====================
                  
                  def comparison_and_copy():
                      print("n容器比较和复制:")
                      
                      # 1. 容器比较
                      print("1. 容器比较:")
                      
                      # 列表比较(按元素逐个比较)
                      list1 = [1, 2, 3]
                      list2 = [1, 2, 3]
                      list3 = [1, 2, 4]
                      
                      print(f"{list1} == {list2}: {list1 == list2}")
                      print(f"{list1} == {list3}: {list1 == list3}")
                      print(f"{list1} != {list3}: {list1 != list3}")
                      
                      # 字典比较(比较键值对)
                      dict1 = {'a': 1, 'b': 2}
                      dict2 = {'b': 2, 'a': 1}  # 顺序不同
                      print(f"{dict1} == {dict2}: {dict1 == dict2}")
                      
                      # 集合比较
                      set1 = {1, 2, 3}
                      set2 = {3, 2, 1}  # 顺序不同
                      print(f"{set1} == {set2}: {set1 == set2}")
                      
                      # 包含关系比较
                      print(f"{set1} 是 {set2} 的超集: {set1 >= set2}")
                      print(f"{set1} 是 {set2} 的子集: {set1 <= set2}")
                      
                      # 2. 浅拷贝(shallow copy)
                      print("n2. 浅拷贝:")
                      
                      original = [[1, 2], [3, 4]]
                      
                      # 列表的浅拷贝方法
                      copy1 = original.copy()          # copy()方法
                      copy2 = list(original)           # 构造函数
                      copy3 = original[:]              # 切片
                      
                      print(f"原始列表: {original}")
                      print(f"浅拷贝1: {copy1}")
                      print(f"浅拷贝2: {copy2}")
                      print(f"浅拷贝3: {copy3}")
                      
                      # 修改原始列表
                      original[0][0] = 100
                      print(f"修改原始列表后:")
                      print(f"原始列表: {original}")
                      print(f"浅拷贝1: {copy1}")  # 也被修改了!
                      print("注意:浅拷贝只复制第一层,嵌套对象是共享的")
                      
                      # 3. 深拷贝(deep copy)
                      print("n3. 深拷贝:")
                      import copy
                      
                      original = [[1, 2], [3, 4]]
                      deep_copy = copy.deepcopy(original)
                      
                      print(f"原始列表: {original}")
                      print(f"深拷贝: {deep_copy}")
                      
                      # 修改原始列表
                      original[0][0] = 100
                      print(f"修改原始列表后:")
                      print(f"原始列表: {original}")
                      print(f"深拷贝: {deep_copy}")  # 未被修改
                      print("注意:深拷贝复制所有嵌套对象")
                      
                      # 4. 复制字典
                      print("n4. 字典复制:")
                      original_dict = {'a': [1, 2], 'b': [3, 4]}
                      
                      # 浅拷贝
                      shallow_dict = original_dict.copy()
                      
                      # 深拷贝
                      deep_dict = copy.deepcopy(original_dict)
                      
                      # 修改原始字典
                      original_dict['a'][0] = 100
                      
                      print(f"原始字典: {original_dict}")
                      print(f"浅拷贝字典: {shallow_dict}")  # 嵌套列表被修改
                      print(f"深拷贝字典: {deep_dict}")      # 未被修改
                      
                      # 5. 复制集合
                      print("n5. 集合复制:")
                      original_set = {1, 2, 3}
                      
                      # 集合复制
                      set_copy = original_set.copy()
                      
                      print(f"原始集合: {original_set}")
                      print(f"复制集合: {set_copy}")
                      
                      # 6. 不可变容器的"复制"
                      print("n6. 不可变容器的'复制':")
                      
                      # 元组是不可变的,所以赋值只是创建引用
                      original_tuple = (1, 2, [3, 4])
                      tuple_reference = original_tuple
                      
                      # 要创建包含可变元素的元组的真正副本
                      import copy
                      tuple_copy = copy.deepcopy(original_tuple)
                      
                      # 修改原始元组中的列表
                      original_tuple[2][0] = 100
                      
                      print(f"原始元组: {original_tuple}")
                      print(f"元组引用: {tuple_reference}")  # 也被修改了
                      print(f"元组深拷贝: {tuple_copy}")     # 未被修改
                      
                      # 7. 性能考虑
                      print("n7. 性能考虑:")
                      
                      # 测试不同复制方法的性能
                      import time
                      
                      large_list = list(range(1000000))
                      
                      # 测试浅拷贝性能
                      start = time.time()
                      shallow_copy = large_list.copy()
                      shallow_time = time.time() - start
                      
                      # 测试切片复制性能
                      start = time.time()
                      slice_copy = large_list[:]
                      slice_time = time.time() - start
                      
                      # 测试构造函数复制性能
                      start = time.time()
                      constructor_copy = list(large_list)
                      constructor_time = time.time() - start
                      
                      print(f"浅拷贝时间: {shallow_time:.6f}秒")
                      print(f"切片复制时间: {slice_time:.6f}秒")
                      print(f"构造函数复制时间: {constructor_time:.6f}秒")
                      print("三种方法性能相近,选择最清晰的方式即可")
                  
                  comparison_and_copy()
                  

                  # ==================== 内置函数与容器操作 ====================
                  
                  def builtin_functions_with_containers():
                      print("n内置函数与容器操作:")
                      
                      # 1. map() - 对容器中每个元素应用函数
                      print("1. map() - 映射:")
                      
                      numbers = [1, 2, 3, 4, 5]
                      
                      # 转换为字符串
                      str_numbers = list(map(str, numbers))
                      print(f"数字转字符串: {numbers} -> {str_numbers}")
                      
                      # 计算平方
                      squares = list(map(lambda x: x**2, numbers))
                      print(f"计算平方: {numbers} -> {squares}")
                      
                      # 2. filter() - 过滤容器元素
                      print("n2. filter() - 过滤:")
                      
                      # 过滤偶数
                      even_numbers = list(filter(lambda x: x % 2 == 0, numbers))
                      print(f"过滤偶数: {numbers} -> {even_numbers}")
                      
                      # 过滤非空字符串
                      strings = ["hello", "", "world", "", "python"]
                      non_empty = list(filter(None, strings))  # None会过滤掉假值
                      print(f"过滤空字符串: {strings} -> {non_empty}")
                      
                      # 3. reduce() - 累积计算(需要functools)
                      print("n3. reduce() - 累积计算:")
                      from functools import reduce
                      
                      # 计算乘积
                      product = reduce(lambda x, y: x * y, numbers)
                      print(f"计算乘积: {numbers} -> {product}")
                      
                      # 连接字符串
                      words = ["Hello", "World", "Python"]
                      concatenated = reduce(lambda x, y: x + " " + y, words)
                      print(f"连接字符串: {words} -> '{concatenated}'")
                      
                      # 4. zip() - 合并多个容器
                      print("n4. zip() - 合并容器:")
                      
                      names = ["Alice", "Bob", "Charlie"]
                      ages = [25, 30, 35]
                      
                      # 合并为元组列表
                      people = list(zip(names, ages))
                      print(f"合并列表: names={names}, ages={ages} -> {people}")
                      
                      # 处理不等长列表
                      list1 = [1, 2, 3]
                      list2 = ['a', 'b', 'c', 'd']
                      combined = list(zip(list1, list2))  # 以最短的为准
                      print(f"不等长合并: {list1}, {list2} -> {combined}")
                      
                      # 5. enumerate() - 带索引的迭代
                      print("n5. enumerate() - 带索引迭代:")
                      
                      fruits = ["apple", "banana", "orange"]
                      print("带索引迭代:")
                      for index, fruit in enumerate(fruits):
                          print(f"  [{index}] {fruit}")
                      
                      # 指定起始索引
                      print("指定起始索引为1:")
                      for index, fruit in enumerate(fruits, start=1):
                          print(f"  [{index}] {fruit}")
                      
                      # 6. sorted() 和 reversed() 的更多用法
                      print("n6. sorted() 和 reversed():")
                      
                      # 复杂对象排序
                      students = [
                          {"name": "Alice", "age": 25},
                          {"name": "Bob", "age": 30},
                          {"name": "Charlie", "age": 22}
                      ]
                      
                      # 按年龄排序
                      sorted_by_age = sorted(students, key=lambda x: x["age"])
                      print(f"按年龄排序: {sorted_by_age}")
                      
                      # 按姓名排序
                      sorted_by_name = sorted(students, key=lambda x: x["name"])
                      print(f"按姓名排序: {sorted_by_name}")
                      
                      # 多级排序
                      from operator import itemgetter
                      
                      data = [
                          ("apple", 3, 1.5),
                          ("banana", 2, 0.8),
                          ("apple", 1, 1.5),
                          ("banana", 3, 0.8)
                      ]
                      
                      # 先按名称,再按数量排序
                      multi_sorted = sorted(data, key=itemgetter(0, 1))
                      print(f"多级排序: {multi_sorted}")
                      
                      # 7. all() 和 any() 的高级用法
                      print("n7. all() 和 any() 的高级用法:")
                      
                      # 检查所有字符串长度大于2
                      strings = ["hello", "world", "python", "go"]
                      all_long = all(len(s) > 2 for s in strings)
                      print(f"所有字符串长度>2: {strings} -> {all_long}")
                      
                      # 检查是否有字符串包含特定字符
                      any_contains_o = any('o' in s for s in strings)
                      print(f"有字符串包含'o': {strings} -> {any_contains_o}")
                      
                      # 8. sum() 的进阶用法
                      print("n8. sum() 的进阶用法:")
                      
                      # 计算嵌套列表总和
                      nested = [[1, 2, 3], [4, 5], [6, 7, 8, 9]]
                      total = sum(sum(sublist) for sublist in nested)
                      print(f"嵌套列表总和: {nested} -> {total}")
                      
                      # 计算字典值总和
                      inventory = {"apples": 10, "bananas": 5, "oranges": 8}
                      total_items = sum(inventory.values())
                      print(f"库存总数: {inventory} -> {total_items}")
                      
                      # 9. 使用iter()和next()的高级模式
                      print("n9. iter()和next()的高级模式:")
                      
                      # 分批处理
                      def batch_process(data, batch_size=3):
                          """将数据分批处理"""
                          it = iter(data)
                          while True:
                              batch = []
                              try:
                                  for _ in range(batch_size):
                                      batch.append(next(it))
                                  yield batch
                              except StopIteration:
                                  if batch:
                                      yield batch
                                  break
                      
                      numbers = list(range(10))
                      print(f"原始数据: {numbers}")
                      print("分批处理:")
                      for i, batch in enumerate(batch_process(numbers, 3), 1):
                          print(f"  批次{i}: {batch}")
                  
                  builtin_functions_with_containers()
                  

                  # ==================== 综合应用示例 ====================
                  
                  def comprehensive_example():
                      print("n综合应用示例:")
                      
                      # 场景:学生成绩管理系统
                      students_data = [
                          {"id": 1, "name": "Alice", "scores": {"math": 85, "english": 90, "science": 88}},
                          {"id": 2, "name": "Bob", "scores": {"math": 78, "english": 85, "science": 92}},
                          {"id": 3, "name": "Charlie", "scores": {"math": 92, "english": 88, "science": 95}},
                          {"id": 4, "name": "Diana", "scores": {"math": 65, "english": 70, "science": 68}},
                      ]
                      
                      # 1. 提取所有学生姓名
                      student_names = [student["name"] for student in students_data]
                      print(f"1. 所有学生姓名: {student_names}")
                      
                      # 2. 计算每个学生的平均分
                      student_averages = []
                      for student in students_data:
                          name = student["name"]
                          scores = student["scores"].values()
                          average = sum(scores) / len(scores) if scores else 0
                          student_averages.append((name, average))
                      
                      print(f"n2. 学生平均分: {student_averages}")
                      
                      # 3. 按平均分排序
                      sorted_students = sorted(student_averages, key=lambda x: x[1], reverse=True)
                      print(f"n3. 按平均分排序: {sorted_students}")
                      
                      # 4. 找出数学成绩最高的学生
                      math_scores = [(student["name"], student["scores"]["math"]) for student in students_data]
                      top_math_student = max(math_scores, key=lambda x: x[1])
                      print(f"n4. 数学最高分: {top_math_student}")
                      
                      # 5. 统计各科目平均分
                      subjects = ["math", "english", "science"]
                      subject_averages = {}
                      
                      for subject in subjects:
                          scores = [student["scores"][subject] for student in students_data]
                          subject_averages[subject] = sum(scores) / len(scores)
                      
                      print(f"n5. 各科目平均分:")
                      for subject, avg in subject_averages.items():
                          print(f"  {subject}: {avg:.2f}")
                      
                      # 6. 找出需要帮助的学生(任一科目低于70分)
                      struggling_students = []
                      for student in students_data:
                          name = student["name"]
                          low_scores = [subject for subject, score in student["scores"].items() if score < 70]
                          if low_scores:
                              struggling_students.append((name, low_scores))
                      
                      print(f"n6. 需要帮助的学生:")
                      for student, low_subjects in struggling_students:
                          print(f"  {student}: {low_subjects}")
                      
                      # 7. 创建成绩报告
                      print("n7. 成绩报告:")
                      report = []
                      for student in students_data:
                          name = student["name"]
                          scores = student["scores"]
                          total = sum(scores.values())
                          average = total / len(scores)
                          
                          # 成绩等级
                          if average >= 90:
                              grade = "A"
                          elif average >= 80:
                              grade = "B"
                          elif average >= 70:
                              grade = "C"
                          elif average >= 60:
                              grade = "D"
                          else:
                              grade = "F"
                          
                          report.append({
                              "name": name,
                              "scores": scores,
                              "average": round(average, 2),
                              "grade": grade
                          })
                      
                      for student_report in report:
                          print(f"  {student_report['name']}: 平均分={student_report['average']}, 等级={student_report['grade']}")
                          print(f"    各科成绩: {student_report['scores']}")
                      
                      # 8. 数据转换:将学生数据转换为不同的格式
                      print("n8. 数据格式转换:")
                      
                      # 转换为CSV格式
                      csv_lines = ["name,math,english,science,average,grade"]
                      for student_report in report:
                          csv_line = f"{student_report['name']},{student_report['scores']['math']},"
                          csv_line += f"{student_report['scores']['english']},{student_report['scores']['science']},"
                          csv_line += f"{student_report['average']},{student_report['grade']}"
                          csv_lines.append(csv_line)
                      
                      print("CSV格式:")
                      for line in csv_lines:
                          print(f"  {line}")
                      
                      # 转换为字典格式(按学科分组)
                      subject_groups = {}
                      for subject in subjects:
                          subject_groups[subject] = {}
                          for student in students_data:
                              subject_groups[subject][student["name"]] = student["scores"][subject]
                      
                      print("n按学科分组:")
                      for subject, scores in subject_groups.items():
                          print(f"  {subject}: {scores}")
                  
                  comprehensive_example()
                  

                  # ==================== 性能考虑与最佳实践 ====================
                  
                  def performance_and_best_practices():
                      print("n性能考虑与最佳实践:")
                      
                      import time
                      import sys
                      
                      # 1. 选择合适的容器类型
                      print("1. 选择合适的容器类型:")
                      
                      # 测试列表和集合的成员测试性能
                      print("测试成员测试性能:")
                      
                      # 创建大数据集
                      large_list = list(range(1000000))
                      large_set = set(large_list)
                      
                      # 测试列表成员测试
                      start = time.time()
                      result = 999999 in large_list
                      list_time = time.time() - start
                      
                      # 测试集合成员测试
                      start = time.time()
                      result = 999999 in large_set
                      set_time = time.time() - start
                      
                      print(f"  列表成员测试时间: {list_time:.6f}秒")
                      print(f"  集合成员测试时间: {set_time:.6f}秒")
                      print(f"  集合比列表快 {list_time/set_time:.1f}倍")
                      
                      # 2. 避免不必要的转换
                      print("n2. 避免不必要的转换:")
                      
                      data = list(range(10000))
                      
                      # 不必要转换
                      start = time.time()
                      for _ in range(1000):
                          temp = list(data)  # 创建不必要的副本
                      unnecessary_time = time.time() - start
                      
                      # 直接使用
                      start = time.time()
                      for _ in range(1000):
                          temp = data  # 直接引用
                      direct_time = time.time() - start
                      
                      print(f"  不必要转换时间: {unnecessary_time:.6f}秒")
                      print(f"  直接使用时间: {direct_time:.6f}秒")
                      
                      # 3. 使用生成器表达式代替列表推导式(节省内存)
                      print("n3. 使用生成器表达式节省内存:")
                      
                      # 大数据集
                      huge_range = range(10000000)
                      
                      # 列表推导式(消耗大量内存)
                      print("  列表推导式内存测试:")
                      start_memory = sys.getsizeof([])
                      
                      # 注意:这里不实际创建,只是演示
                      # huge_list = [x**2 for x in huge_range]  # 这会消耗大量内存
                      
                      # 生成器表达式(节省内存)
                      print("  生成器表达式内存测试:")
                      huge_gen = (x**2 for x in huge_range)
                      gen_memory = sys.getsizeof(huge_gen)
                      
                      print(f"  生成器对象大小: {gen_memory}字节")
                      print("  生成器只在迭代时生成值,不预先生成所有值")
                      
                      # 4. 使用内置函数和库函数
                      print("n4. 使用内置函数和库函数:")
                      
                      numbers = list(range(1000000))
                      
                      # 手动求最大值
                      start = time.time()
                      max_value = numbers[0]
                      for num in numbers:
                          if num > max_value:
                              max_value = num
                      manual_time = time.time() - start
                      
                      # 使用内置max函数
                      start = time.time()
                      max_value = max(numbers)
                      builtin_time = time.time() - start
                      
                      print(f"  手动求最大值时间: {manual_time:.6f}秒")
                      print(f"  内置max函数时间: {builtin_time:.6f}秒")
                      
                      # 5. 批量操作 vs 逐个操作
                      print("n5. 批量操作 vs 逐个操作:")
                      
                      # 创建测试数据
                      strings = ["hello"] * 10000
                      
                      # 逐个连接(低效)
                      start = time.time()
                      result = ""
                      for s in strings:
                          result += s
                      concat_time = time.time() - start
                      
                      # 批量连接(高效)
                      start = time.time()
                      result = "".join(strings)
                      join_time = time.time() - start
                      
                      print(f"  逐个连接时间: {concat_time:.6f}秒")
                      print(f"  批量连接时间: {join_time:.6f}秒")
                      print(f"  join()比逐个连接快 {concat_time/join_time:.1f}倍")
                      
                      # 6. 适当使用切片
                      print("n6. 适当使用切片:")
                      
                      data = list(range(1000000))
                      
                      # 复制列表的不同方法
                      start = time.time()
                      for _ in range(100):
                          copy1 = data[:]
                      slice_time = time.time() - start
                      
                      start = time.time()
                      for _ in range(100):
                          copy2 = list(data)
                      list_time = time.time() - start
                      
                      start = time.time()
                      for _ in range(100):
                          copy3 = data.copy()
                      copy_time = time.time() - start
                      
                      print(f"  切片复制时间: {slice_time:.6f}秒")
                      print(f"  构造函数复制时间: {list_time:.6f}秒")
                      print(f"  copy()方法时间: {copy_time:.6f}秒")
                      print("  三种方法性能相似,选择最清晰的方式")
                      
                      # 7. 总结建议
                      print("n7. 最佳实践总结:")
                      print("  - 频繁成员测试时使用集合(set)而不是列表(list)")
                      print("  - 使用生成器表达式处理大数据节省内存")
                      print("  - 优先使用内置函数和库函数")
                      print("  - 字符串操作使用join()而不是循环拼接")
                      print("  - 避免不必要的容器转换和复制")
                      print("  - 使用切片进行高效复制和操作")
                      print("  - 根据需求选择合适的容器类型")
                  
                  performance_and_best_practices()
                  

                  1. 类型间转换:使用目标类型的构造函数(如list(), tuple(), set(), dict()
                  2. 字典转换:使用dict()zip()组合,或直接从键值对列表转换
                  3. 字符串转换:使用str()join()方法
                  4. 去重转换:使用set()可以快速去重

                  1. 通用函数len(), max(), min(), sum(), sorted(), reversed()
                  2. 成员测试:使用innot in操作符
                  3. 迭代操作for循环,enumerate(), zip()
                  4. 切片操作:适用于所有序列类型(列表、元组、字符串)
                  5. 比较操作==, !=, >, <等(不同类型容器比较规则不同)

                  1. 选择合适容器:根据操作类型选择最有效的容器
                  2. 使用内置函数:它们通常经过优化,比手动实现更快
                  3. 避免不必要转换:特别是大数据集
                  4. 批量操作优先:如使用join()而非循环拼接字符串
                  5. 注意深浅拷贝:根据需求选择正确的复制方式

                  掌握容器转换和共有函数是Python编程的基础,能够大大提高代码的简洁性和效率。

                  C++标准模板库(STL)提供了多种容器,分为序列容器、关联容器和无序关联容器。

                  容器类型 描述 头文件 示例
                  vector 动态数组 <vector> vector<int> v = {1,2,3};
                  deque 双端队列 <deque> deque<int> d = {1,2,3};
                  list 双向链表 <list> list<int> l = {1,2,3};
                  forward_list 单向链表 <forward_list> forward_list<int> fl = {1,2,3};
                  array 固定大小数组 <array> array<int,3> a = {1,2,3};
                  set 有序唯一键集合 <set> set<int> s = {1,2,3};
                  multiset 有序集合(允许多个相同键) <set> multiset<int> ms = {1,2,2,3};
                  map 有序键值对映射 <map> map<string,int> m = {{"a",1},{"b",2}};
                  multimap 有序映射(允许多个相同键) <map> multimap<string,int> mm = {{"a",1},{"a",2}};
                  unordered_set 无序唯一键集合 <unordered_set> unordered_set<int> us = {1,2,3};
                  unordered_multiset 无序集合(允许多个相同键) <unordered_set> unordered_multiset<int> ums = {1,2,2,3};
                  unordered_map 无序键值对映射 <unordered_map> unordered_map<string,int> um = {{"a",1},{"b",2}};
                  unordered_multimap 无序映射(允许多个相同键) <unordered_map> unordered_multimap<string,int> umm = {{"a",1},{"a",2}};
                  stack 栈(适配器) <stack> stack<int> st;
                  queue 队列(适配器) <queue> queue<int> q;
                  priority_queue 优先队列(适配器) <queue> priority_queue<int> pq;

                  在C++中,容器之间的转换通常通过构造函数、赋值操作或标准库算法来实现。由于C++是强类型语言,转换时需要考虑类型匹配和性能。

                  #include <iostream>
                  #include <vector>
                  #include <list>
                  #include <set>
                  #include <map>
                  #include <unordered_set>
                  #include <algorithm>
                  
                  int main() {
                      // 1. 从数组或初始化列表构造
                      int arr[] = {1, 2, 3, 2, 1};
                      std::vector<int> vec(std::begin(arr), std::end(arr));
                      std::cout << "vector from array: ";
                      for (int x : vec) std::cout << x << ' ';
                      std::cout << 'n';
                  
                      // 2. 从vector构造list
                      std::list<int> lst(vec.begin(), vec.end());
                      std::cout << "list from vector: ";
                      for (int x : lst) std::cout << x << ' ';
                      std::cout << 'n';
                  
                      // 3. 从vector构造set(自动去重和排序)
                      std::set<int> s(vec.begin(), vec.end());
                      std::cout << "set from vector (sorted and unique): ";
                      for (int x : s) std::cout << x << ' ';
                      std::cout << 'n';
                  
                      // 4. 从vector构造unordered_set(去重,无序)
                      std::unordered_set<int> us(vec.begin(), vec.end());
                      std::cout << "unordered_set from vector (unique, unordered): ";
                      for (int x : us) std::cout << x << ' ';
                      std::cout << 'n';
                  
                      // 5. 将set转换为vector
                      std::vector<int> vec2(s.begin(), s.end());
                      std::cout << "vector from set: ";
                      for (int x : vec2) std::cout << x << ' ';
                      std::cout << 'n';
                  
                      // 6. 将两个vector组合成map
                      std::vector<std::string> keys = {"one", "two", "three"};
                      std::vector<int> values = {1, 2, 3};
                      std::map<std::string, int> m;
                      for (size_t i = 0; i < keys.size() && i < values.size(); ++i) {
                          m[keys[i]] = values[i];
                      }
                      std::cout << "map from two vectors: ";
                      for (const auto& p : m) std::cout << p.first << ":" << p.second << ' ';
                      std::cout << 'n';
                  
                      // 使用std::transform和std::inserter
                      std::map<std::string, int> m2;
                      std::transform(keys.begin(), keys.end(), values.begin(),
                                     std::inserter(m2, m2.end()),
                                     [](const std::string& k, int v) { return std::make_pair(k, v); });
                      std::cout << "map using transform: ";
                      for (const auto& p : m2) std::cout << p.first << ":" << p.second << ' ';
                      std::cout << 'n';
                  
                      return 0;
                  }
                  

                  #include <iostream>
                  #include <vector>
                  #include <list>
                  
                  int main() {
                      std::vector<int> vec = {1, 2, 3, 4, 5};
                      std::list<int> lst;
                  
                      // 使用assign方法(会覆盖原有内容)
                      lst.assign(vec.begin(), vec.end());
                      std::cout << "list after assign from vector: ";
                      for (int x : lst) std::cout << x << ' ';
                      std::cout << 'n';
                  
                      // 使用swap交换两个相同类型的容器(常数时间)
                      std::vector<int> vec2 = {10, 20, 30};
                      std::cout << "before swap:n";
                      std::cout << "vec: "; for (int x : vec) std::cout << x << ' '; std::cout << 'n';
                      std::cout << "vec2: "; for (int x : vec2) std::cout << x << ' '; std::cout << 'n';
                  
                      vec.swap(vec2);
                      std::cout << "after swap:n";
                      std::cout << "vec: "; for (int x : vec) std::cout << x << ' '; std::cout << 'n';
                      std::cout << "vec2: "; for (int x : vec2) std::cout << x << ' '; std::cout << 'n';
                  
                      // 使用std::swap也可以
                      std::swap(vec, vec2);
                      std::cout << "after std::swap:n";
                      std::cout << "vec: "; for (int x : vec) std::cout << x << ' '; std::cout << 'n';
                      std::cout << "vec2: "; for (int x : vec2) std::cout << x << ' '; std::cout << 'n';
                  
                      return 0;
                  }
                  

                  #include <iostream>
                  #include <vector>
                  #include <set>
                  #include <algorithm>
                  #include <iterator>
                  
                  int main() {
                      std::vector<int> vec = {5, 3, 1, 4, 2, 3, 1};
                  
                      // 复制到另一个vector
                      std::vector<int> vec2;
                      std::copy(vec.begin(), vec.end(), std::back_inserter(vec2));
                      std::cout << "copy to vec2: ";
                      for (int x : vec2) std::cout << x << ' ';
                      std::cout << 'n';
                  
                      // 复制到set(去重和排序)
                      std::set<int> s;
                      std::copy(vec.begin(), vec.end(), std::inserter(s, s.begin()));
                      std::cout << "copy to set: ";
                      for (int x : s) std::cout << x << ' ';
                      std::cout << 'n';
                  
                      // 使用std::transform进行转换
                      std::vector<int> vec3;
                      std::transform(vec.begin(), vec.end(), std::back_inserter(vec3),
                                     [](int x) { return x * 2; });
                      std::cout << "transform (double): ";
                      for (int x : vec3) std::cout << x << ' ';
                      std::cout << 'n';
                  
                      // 使用std::remove_copy_if过滤
                      std::vector<int> vec4;
                      std::remove_copy_if(vec.begin(), vec.end(), std::back_inserter(vec4),
                                          [](int x) { return x % 2 == 0; });
                      std::cout << "remove_copy_if (remove even): ";
                      for (int x : vec4) std::cout << x << ' ';
                      std::cout << 'n';
                  
                      // 使用std::unique_copy去重(需要先排序)
                      std::vector<int> vec5;
                      std::sort(vec.begin(), vec.end());
                      std::unique_copy(vec.begin(), vec.end(), std::back_inserter(vec5));
                      std::cout << "unique_copy after sorting: ";
                      for (int x : vec5) std::cout << x << ' ';
                      std::cout << 'n';
                  
                      return 0;
                  }
                  

                  #include <iostream>
                  #include <vector>
                  #include <list>
                  #include <set>
                  #include <map>
                  
                  void container_common_functions() {
                      std::cout << "=== 容器共有函数 ===n";
                      
                      // 1. 构造函数和析构函数
                      std::vector<int> v1 = {1, 2, 3};           // 初始化列表构造函数
                      std::vector<int> v2(v1.begin(), v1.end()); // 范围构造函数
                      std::vector<int> v3(5, 10);                // 数量+值构造函数
                      
                      // 2. 赋值操作
                      std::vector<int> v4;
                      v4 = v1;                                   // 拷贝赋值
                      v4 = {4, 5, 6};                            // 初始化列表赋值
                      v4.assign(3, 7);                           // assign方法
                      v4.assign(v1.begin(), v1.end());           // 范围assign
                      
                      // 3. 迭代器
                      std::cout << "迭代器: ";
                      for (auto it = v1.begin(); it != v1.end(); ++it) {
                          std::cout << *it << " ";
                      }
                      std::cout << "n";
                      
                      std::cout << "反向迭代器: ";
                      for (auto it = v1.rbegin(); it != v1.rend(); ++it) {
                          std::cout << *it << " ";
                      }
                      std::cout << "n";
                      
                      // 4. 容量相关
                      std::cout << "size: " << v1.size() << "n";
                      std::cout << "max_size: " << v1.max_size() << "n";
                      std::cout << "empty: " << std::boolalpha << v1.empty() << "n";
                      
                      // vector特有的容量操作
                      v1.reserve(10);
                      std::cout << "capacity: " << v1.capacity() << "n";
                      v1.shrink_to_fit();
                      
                      // 5. 元素访问
                      if (!v1.empty()) {
                          std::cout << "front: " << v1.front() << "n";
                          std::cout << "back: " << v1.back() << "n";
                      }
                      
                      // 6. 修改器
                      v1.push_back(4);
                      v1.pop_back();
                      
                      v1.insert(v1.begin() + 1, 99);
                      v1.erase(v1.begin() + 1);
                      
                      v1.clear();
                      
                      // 7. 交换
                      std::vector<int> v5 = {10, 20, 30};
                      v1.swap(v5);
                      
                      // 8. 比较操作
                      std::vector<int> a = {1, 2, 3};
                      std::vector<int> b = {1, 2, 3};
                      std::cout << "a == b: " << (a == b) << "n";
                      std::cout << "a < b: " << (a < b) << "n";
                  }
                  

                  #include <iostream>
                  #include <vector>
                  #include <deque>
                  #include <list>
                  #include <forward_list>
                  #include <array>
                  
                  void sequence_container_specific() {
                      std::cout << "n=== 序列容器特有操作 ===n";
                      
                      // 1. vector - 动态数组
                      std::vector<int> vec = {1, 2, 3};
                      
                      // 随机访问
                      std::cout << "vector[1]: " << vec[1] << "n";
                      std::cout << "vector.at(1): " << vec.at(1) << "n";
                      
                      // 调整大小
                      vec.resize(5, 0);  // 扩展,新增元素初始化为0
                      std::cout << "after resize(5): ";
                      for (int x : vec) std::cout << x << " ";
                      std::cout << "n";
                      
                      vec.resize(2);     // 缩小
                      std::cout << "after resize(2): ";
                      for (int x : vec) std::cout << x << " ";
                      std::cout << "n";
                      
                      // 2. deque - 双端队列
                      std::deque<int> dq = {1, 2, 3};
                      
                      dq.push_front(0);   // 前端插入
                      dq.push_back(4);    // 后端插入
                      
                      dq.pop_front();     // 前端删除
                      dq.pop_back();      // 后端删除
                      
                      // 3. list - 双向链表
                      std::list<int> lst = {1, 2, 3};
                      
                      // 链表特有操作
                      lst.push_front(0);
                      lst.pop_front();
                      
                      // 合并、拼接
                      std::list<int> lst2 = {4, 5, 6};
                      lst.merge(lst2);
                      
                      lst.sort();         // 链表排序(成员函数)
                      lst.unique();       // 删除连续重复元素
                      
                      // 4. forward_list - 单向链表
                      std::forward_list<int> flist = {1, 2, 3};
                      
                      // 只有push_front,没有push_back
                      flist.push_front(0);
                      flist.pop_front();
                      
                      // 5. array - 固定大小数组
                      std::array<int, 3> arr = {1, 2, 3};
                      
                      // array特有:fill方法
                      arr.fill(7);
                      std::cout << "array after fill(7): ";
                      for (int x : arr) std::cout << x << " ";
                      std::cout << "n";
                  }
                  

                  #include <iostream>
                  #include <set>
                  #include <map>
                  #include <unordered_set>
                  #include <unordered_map>
                  
                  void associative_container_specific() {
                      std::cout << "n=== 关联容器特有操作 ===n";
                      
                      // 1. set/multiset
                      std::set<int> s = {3, 1, 4, 1, 5, 9};
                      std::multiset<int> ms = {3, 1, 4, 1, 5, 9};
                      
                      // 插入
                      auto result = s.insert(2);
                      std::cout << "插入2: " << (result.second ? "成功" : "失败") << "n";
                      
                      // 查找
                      auto it = s.find(3);
                      if (it != s.end()) {
                          std::cout << "找到3n";
                      }
                      
                      // 计数
                      std::cout << "set中1的个数: " << s.count(1) << "n";
                      std::cout << "multiset中1的个数: " << ms.count(1) << "n";
                      
                      // 范围查找
                      auto lower = s.lower_bound(2);  // 第一个>=2的元素
                      auto upper = s.upper_bound(5);  // 第一个>5的元素
                      auto range = s.equal_range(4);  // 等于4的范围
                      
                      // 2. map/multimap
                      std::map<std::string, int> m = {{"apple", 1}, {"banana", 2}};
                      std::multimap<std::string, int> mm = {{"apple", 1}, {"apple", 2}};
                      
                      // 插入
                      m.insert({"orange", 3});
                      m.emplace("pear", 4);
                      
                      // 访问(map特有)
                      std::cout << "apple: " << m["apple"] << "n";
                      std::cout << "orange: " << m.at("orange") << "n";
                      
                      // 3. 无序容器特有操作
                      std::unordered_set<int> us = {1, 2, 3, 4, 5};
                      std::unordered_map<std::string, int> um = {{"a", 1}, {"b", 2}};
                      
                      // 桶接口
                      std::cout << "桶数量: " << us.bucket_count() << "n";
                      std::cout << "负载因子: " << us.load_factor() << "n";
                      
                      // 重新哈希
                      us.rehash(20);
                      us.reserve(100);
                      
                      // 遍历桶
                      for (size_t i = 0; i < us.bucket_count(); ++i) {
                          std::cout << "桶" << i << "有" << us.bucket_size(i) << "个元素n";
                      }
                  }
                  

                  #include <iostream>
                  #include <stack>
                  #include <queue>
                  #include <vector>
                  #include <deque>
                  
                  void container_adapter_specific() {
                      std::cout << "n=== 容器适配器特有操作 ===n";
                      
                      // 1. stack - 栈
                      std::stack<int> st;
                      
                      st.push(1);
                      st.push(2);
                      st.push(3);
                      
                      std::cout << "栈顶: " << st.top() << "n";
                      st.pop();
                      std::cout << "弹出后栈顶: " << st.top() << "n";
                      
                      // 2. queue - 队列
                      std::queue<int> q;
                      
                      q.push(1);
                      q.push(2);
                      q.push(3);
                      
                      std::cout << "队首: " << q.front() << "n";
                      std::cout << "队尾: " << q.back() << "n";
                      q.pop();
                      std::cout << "弹出后队首: " << q.front() << "n";
                      
                      // 3. priority_queue - 优先队列
                      std::priority_queue<int> pq;
                      
                      pq.push(3);
                      pq.push(1);
                      pq.push(4);
                      pq.push(2);
                      
                      std::cout << "优先队列: ";
                      while (!pq.empty()) {
                          std::cout << pq.top() << " ";
                          pq.pop();
                      }
                      std::cout << "n";
                      
                      // 自定义比较器的优先队列(最小堆)
                      std::priority_queue<int, std::vector<int>, std::greater<int>> min_pq;
                      min_pq.push(3);
                      min_pq.push(1);
                      min_pq.push(4);
                      
                      std::cout << "最小堆优先队列: ";
                      while (!min_pq.empty()) {
                          std::cout << min_pq.top() << " ";
                          min_pq.pop();
                      }
                      std::cout << "n";
                  }
                  

                  #include <iostream>
                  #include <vector>
                  #include <list>
                  #include <iterator>
                  #include <algorithm>
                  
                  void iterator_utilities() {
                      std::cout << "n=== 迭代器工具 ===n";
                      
                      std::vector<int> vec = {1, 2, 3, 4, 5};
                      
                      // 1. 迭代器适配器
                      // back_inserter
                      std::vector<int> dest;
                      std::copy(vec.begin(), vec.end(), std::back_inserter(dest));
                      
                      // front_inserter(需要支持push_front的容器)
                      std::list<int> lst;
                      std::copy(vec.begin(), vec.end(), std::front_inserter(lst));
                      
                      // inserter(在指定位置插入)
                      std::vector<int> vec2;
                      std::copy(vec.begin(), vec.end(), std::inserter(vec2, vec2.begin()));
                      
                      // 2. 流迭代器
                      std::cout << "使用ostream_iterator输出: ";
                      std::copy(vec.begin(), vec.end(), std::ostream_iterator<int>(std::cout, " "));
                      std::cout << "n";
                      
                      // 3. 反向迭代器
                      std::cout << "反向输出: ";
                      std::copy(vec.rbegin(), vec.rend(), std::ostream_iterator<int>(std::cout, " "));
                      std::cout << "n";
                      
                      // 4. 移动迭代器(C++11)
                      std::vector<std::string> strings = {"hello", "world"};
                      std::vector<std::string> strings2;
                      
                      // 使用移动迭代器转移资源
                      strings2.insert(strings2.begin(),
                                     std::make_move_iterator(strings.begin()),
                                     std::make_move_iterator(strings.end()));
                      
                      std::cout << "移动后原vector大小: " << strings.size() << "n";
                      std::cout << "目标vector大小: " << strings2.size() << "n";
                  }
                  

                  #include <iostream>
                  #include <vector>
                  #include <algorithm>
                  #include <numeric>
                  #include <execution>  // C++17 并行算法
                  
                  void algorithm_utilities() {
                      std::cout << "n=== 算法库工具 ===n";
                      
                      std::vector<int> vec = {5, 3, 1, 4, 2, 6, 8, 7};
                      
                      // 1. 排序和查找
                      std::sort(vec.begin(), vec.end());
                      std::cout << "排序后: ";
                      for (int x : vec) std::cout << x << " ";
                      std::cout << "n";
                      
                      bool found = std::binary_search(vec.begin(), vec.end(), 4);
                      std::cout << "二分查找4: " << (found ? "找到" : "未找到") << "n";
                      
                      // 2. 数值算法
                      int sum = std::accumulate(vec.begin(), vec.end(), 0);
                      int product = std::accumulate(vec.begin(), vec.end(), 1, std::multiplies<int>());
                      
                      std::cout << "和: " << sum << "n";
                      std::cout << "积: " << product << "n";
                      
                      // 3. 变换
                      std::vector<int> transformed;
                      std::transform(vec.begin(), vec.end(), std::back_inserter(transformed),
                                     [](int x) { return x * 2; });
                      
                      // 4. 过滤
                      std::vector<int> filtered;
                      std::copy_if(vec.begin(), vec.end(), std::back_inserter(filtered),
                                   [](int x) { return x % 2 == 0; });
                      
                      // 5. 并行算法(C++17)
                      std::vector<int> large_vec(1000000);
                      std::iota(large_vec.begin(), large_vec.end(), 0);
                      
                      // 并行排序
                      std::sort(std::execution::par, large_vec.begin(), large_vec.end());
                      
                      // 6. 范围算法(C++20概念)
                      #if __cplusplus >= 202002L
                      std::ranges::sort(vec);
                      #endif
                  }
                  

                  #if __cplusplus >= 202002L
                  
                  #include <iostream>
                  #include <vector>
                  #include <ranges>
                  #include <algorithm>
                  
                  void ranges_and_views() {
                      std::cout << "n=== C++20 范围和视图 ===n";
                      
                      std::vector<int> vec = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
                      
                      // 1. 范围算法
                      std::ranges::sort(vec);
                      auto found = std::ranges::find(vec, 5);
                      
                      // 2. 视图(惰性求值)
                      auto even_squares = vec 
                          | std::views::filter([](int x) { return x % 2 == 0; })
                          | std::views::transform([](int x) { return x * x; });
                      
                      std::cout << "偶数的平方: ";
                      for (int x : even_squares) {
                          std::cout << x << " ";
                      }
                      std::cout << "n";
                      
                      // 3. 更多视图操作
                      // 取前5个元素
                      auto first5 = vec | std::views::take(5);
                      
                      // 跳过前3个元素
                      auto skip3 = vec | std::views::drop(3);
                      
                      // 反转
                      auto reversed = vec | std::views::reverse;
                      
                      // 4. 管道操作符组合
                      auto result = vec
                          | std::views::filter([](int x) { return x > 5; })
                          | std::views::transform([](int x) { return x * 2; })
                          | std::views::take(3);
                      
                      std::cout << "管道操作结果: ";
                      for (int x : result) {
                          std::cout << x << " ";
                      }
                      std::cout << "n";
                  }
                  
                  #endif
                  

                  #include <iostream>
                  #include <vector>
                  #include <list>
                  #include <set>
                  #include <type_traits>
                  
                  void type_conversion_utilities() {
                      std::cout << "n=== 类型转换工具 ===n";
                      
                      // 1. 使用std::common_type获取公共类型
                      using type1 = std::common_type_t<int, double>;
                      using type2 = std::common_type_t<int, float, double>;
                      
                      std::cout << "int和double的公共类型: " << typeid(type1).name() << "n";
                      std::cout << "int, float, double的公共类型: " << typeid(type2).name() << "n";
                      
                      // 2. 使用decay去掉引用和const
                      using decayed = std::decay_t<const int&>;
                      std::cout << "const int& decay后: " << typeid(decayed).name() << "n";
                      
                      // 3. 判断类型特性
                      std::cout << "vector<int>是容器: " 
                                << std::boolalpha 
                                << std::is_same_v<decltype(std::begin(std::vector<int>{})),
                                                 typename std::vector<int>::iterator> << "n";
                      
                      // 4. 条件类型选择
                      constexpr bool use_vector = true;
                      using Container = std::conditional_t<use_vector, 
                                                          std::vector<int>, 
                                                          std::list<int>>;
                      
                      Container c = {1, 2, 3};
                      std::cout << "使用的容器类型: " << typeid(c).name() << "n";
                  }
                  

                  #include <iostream>
                  #include <vector>
                  #include <memory>
                  #include <algorithm>
                  
                  void smart_pointers_with_containers() {
                      std::cout << "n=== 智能指针与容器 ===n";
                      
                      // 1. 容器存储unique_ptr
                      std::vector<std::unique_ptr<int>> vec;
                      
                      vec.push_back(std::make_unique<int>(10));
                      vec.push_back(std::make_unique<int>(20));
                      vec.push_back(std::make_unique<int>(30));
                      
                      // 遍历unique_ptr容器
                      for (const auto& ptr : vec) {
                          std::cout << *ptr << " ";
                      }
                      std::cout << "n";
                      
                      // 2. 容器存储shared_ptr
                      std::vector<std::shared_ptr<int>> shared_vec;
                      
                      auto p1 = std::make_shared<int>(100);
                      auto p2 = p1;  // 共享所有权
                      
                      shared_vec.push_back(p1);
                      shared_vec.push_back(p2);
                      
                      std::cout << "引用计数: " << p1.use_count() << "n";
                      
                      // 3. 使用weak_ptr避免循环引用
                      struct Node {
                          std::weak_ptr<Node> next;
                          int value;
                          
                          Node(int v) : value(v) {}
                      };
                      
                      auto node1 = std::make_shared<Node>(1);
                      auto node2 = std::make_shared<Node>(2);
                      
                      node1->next = node2;
                      node2->next = node1;  // weak_ptr不会增加引用计数
                  }
                  

                  #include <iostream>
                  #include <vector>
                  #include <list>
                  #include <chrono>
                  #include <algorithm>
                  
                  void performance_optimization() {
                      std::cout << "n=== 性能优化技巧 ===n";
                      
                      const size_t N = 1000000;
                      
                      // 1. 预分配内存
                      {
                          std::vector<int> v1;
                          auto start = std::chrono::high_resolution_clock::now();
                          for (size_t i = 0; i < N; ++i) {
                              v1.push_back(i);
                          }
                          auto end = std::chrono::high_resolution_clock::now();
                          auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
                          std::cout << "无预分配插入" << N << "个元素: " << duration.count() << " msn";
                      }
                      
                      {
                          std::vector<int> v2;
                          v2.reserve(N);
                          auto start = std::chrono::high_resolution_clock::now();
                          for (size_t i = 0; i < N; ++i) {
                              v2.push_back(i);
                          }
                          auto end = std::chrono::high_resolution_clock::now();
                          auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
                          std::cout << "预分配后插入" << N << "个元素: " << duration.count() << " msn";
                      }
                      
                      // 2. 使用emplace代替insert
                      std::vector<std::pair<int, std::string>> v;
                      
                      // 低效:创建临时对象然后复制
                      v.push_back(std::make_pair(1, "one"));
                      
                      // 高效:直接在容器中构造
                      v.emplace_back(2, "two");
                      
                      // 3. 使用移动语义
                      std::string large_string = "这是一个很长的字符串...";
                      
                      std::vector<std::string> strings;
                      strings.push_back(std::move(large_string));  // 移动而非复制
                      
                      // 4. 选择合适的算法
                      std::vector<int> data(N);
                      std::iota(data.begin(), data.end(), 0);
                      
                      // 线性查找
                      auto start = std::chrono::high_resolution_clock::now();
                      auto it1 = std::find(data.begin(), data.end(), N/2);
                      auto end = std::chrono::high_resolution_clock::now();
                      auto duration1 = std::chrono::duration_cast<std::chrono::microseconds>(end - start);
                      
                      // 二分查找(需要先排序)
                      std::sort(data.begin(), data.end());
                      start = std::chrono::high_resolution_clock::now();
                      bool found = std::binary_search(data.begin(), data.end(), N/2);
                      end = std::chrono::high_resolution_clock::now();
                      auto duration2 = std::chrono::duration_cast<std::chrono::microseconds>(end - start);
                      
                      std::cout << "线性查找时间: " << duration1.count() << " μsn";
                      std::cout << "二分查找时间: " << duration2.count() << " μsn";
                  }
                  

                  #include <iostream>
                  #include <vector>
                  #include <memory>
                  #include <list>
                  
                  // 简单的内存池分配器
                  template<typename T>
                  class SimplePoolAllocator {
                  public:
                      using value_type = T;
                      
                      SimplePoolAllocator() = default;
                      
                      template<typename U>
                      SimplePoolAllocator(const SimplePoolAllocator<U>&) {}
                      
                      T* allocate(std::size_t n) {
                          std::cout << "分配 " << n << " 个 " << typeid(T).name() << " 对象n";
                          return static_cast<T*>(::operator new(n * sizeof(T)));
                      }
                      
                      void deallocate(T* p, std::size_t n) {
                          std::cout << "释放 " << n << " 个 " << typeid(T).name() << " 对象n";
                          ::operator delete(p);
                      }
                  };
                  
                  template<typename T, typename U>
                  bool operator==(const SimplePoolAllocator<T>&, const SimplePoolAllocator<U>&) {
                      return true;
                  }
                  
                  template<typename T, typename U>
                  bool operator!=(const SimplePoolAllocator<T>&, const SimplePoolAllocator<U>&) {
                      return false;
                  }
                  
                  void custom_allocator_example() {
                      std::cout << "n=== 自定义分配器示例 ===n";
                      
                      // 使用自定义分配器的vector
                      std::vector<int, SimplePoolAllocator<int>> vec;
                      
                      vec.push_back(1);
                      vec.push_back(2);
                      vec.push_back(3);
                      
                      std::cout << "vector元素: ";
                      for (int x : vec) std::cout << x << " ";
                      std::cout << "n";
                      
                      // 使用自定义分配器的list
                      std::list<int, SimplePoolAllocator<int>> lst;
                      
                      lst.push_back(10);
                      lst.push_back(20);
                      lst.push_back(30);
                  }
                  

                  #include <iostream>
                  #include <vector>
                  #include <map>
                  #include <set>
                  #include <algorithm>
                  #include <numeric>
                  #include <string>
                  #include <iomanip>
                  
                  struct Student {
                      int id;
                      std::string name;
                      std::map<std::string, double> scores;  // 科目 -> 分数
                      
                      double average_score() const {
                          if (scores.empty()) return 0.0;
                          double sum = std::accumulate(scores.begin(), scores.end(), 0.0,
                              [](double acc, const auto& pair) { return acc + pair.second; });
                          return sum / scores.size();
                      }
                      
                      void add_score(const std::string& subject, double score) {
                          scores[subject] = score;
                      }
                  };
                  
                  class GradeBook {
                  private:
                      std::vector<Student> students;
                      std::set<std::string> subjects;
                      
                  public:
                      // 添加学生
                      void add_student(int id, const std::string& name) {
                          students.push_back({id, name, {}});
                      }
                      
                      // 添加成绩
                      void add_score(int student_id, const std::string& subject, double score) {
                          auto it = std::find_if(students.begin(), students.end(),
                                                [student_id](const Student& s) { 
                                                    return s.id == student_id; 
                                                });
                          if (it != students.end()) {
                              it->add_score(subject, score);
                              subjects.insert(subject);
                          }
                      }
                      
                      // 计算每个学生的平均分
                      std::map<int, double> calculate_averages() const {
                          std::map<int, double> result;
                          for (const auto& student : students) {
                              result[student.id] = student.average_score();
                          }
                          return result;
                      }
                      
                      // 按平均分排序学生
                      std::vector<std::pair<int, double>> sort_by_average() const {
                          auto averages = calculate_averages();
                          std::vector<std::pair<int, double>> sorted(averages.begin(), averages.end());
                          
                          std::sort(sorted.begin(), sorted.end(),
                                   [](const auto& a, const auto& b) {
                                       return a.second > b.second;  // 降序
                                   });
                          
                          return sorted;
                      }
                      
                      // 计算每科平均分
                      std::map<std::string, double> calculate_subject_averages() const {
                          std::map<std::string, double> result;
                          
                          for (const auto& subject : subjects) {
                              double sum = 0.0;
                              int count = 0;
                              
                              for (const auto& student : students) {
                                  auto it = student.scores.find(subject);
                                  if (it != student.scores.end()) {
                                      sum += it->second;
                                      ++count;
                                  }
                              }
                              
                              if (count > 0) {
                                  result[subject] = sum / count;
                              }
                          }
                          
                          return result;
                      }
                      
                      // 生成报告
                      void generate_report() const {
                          std::cout << "n=== 学生成绩报告 ===n";
                          
                          // 学生成绩表
                          std::cout << "n学生成绩详情:n";
                          std::cout << std::setw(5) << "ID" 
                                    << std::setw(10) << "姓名";
                          
                          for (const auto& subject : subjects) {
                              std::cout << std::setw(10) << subject;
                          }
                          std::cout << std::setw(10) << "平均分n";
                          
                          for (const auto& student : students) {
                              std::cout << std::setw(5) << student.id 
                                        << std::setw(10) << student.name;
                              
                              for (const auto& subject : subjects) {
                                  auto it = student.scores.find(subject);
                                  if (it != student.scores.end()) {
                                      std::cout << std::setw(10) << std::fixed 
                                                << std::setprecision(2) << it->second;
                                  } else {
                                      std::cout << std::setw(10) << "N/A";
                                  }
                              }
                              
                              std::cout << std::setw(10) << std::fixed 
                                        << std::setprecision(2) << student.average_score() << "n";
                          }
                          
                          // 按平均分排序
                          std::cout << "n按平均分排名:n";
                          auto sorted = sort_by_average();
                          for (size_t i = 0; i < sorted.size(); ++i) {
                              std::cout << i + 1 << ". 学生ID: " << sorted[i].first 
                                        << ", 平均分: " << sorted[i].second << "n";
                          }
                          
                          // 科目平均分
                          std::cout << "n科目平均分:n";
                          auto subject_averages = calculate_subject_averages();
                          for (const auto& [subject, avg] : subject_averages) {
                              std::cout << subject << ": " << avg << "n";
                          }
                      }
                  };
                  
                  int main() {
                      GradeBook gradebook;
                      
                      // 添加学生
                      gradebook.add_student(1, "张三");
                      gradebook.add_student(2, "李四");
                      gradebook.add_student(3, "王五");
                      
                      // 添加成绩
                      gradebook.add_score(1, "数学", 85.5);
                      gradebook.add_score(1, "英语", 90.0);
                      gradebook.add_score(1, "物理", 88.0);
                      
                      gradebook.add_score(2, "数学", 78.0);
                      gradebook.add_score(2, "英语", 85.0);
                      gradebook.add_score(2, "物理", 92.5);
                      
                      gradebook.add_score(3, "数学", 92.0);
                      gradebook.add_score(3, "英语", 88.5);
                      gradebook.add_score(3, "物理", 95.0);
                      
                      // 生成报告
                      gradebook.generate_report();
                      
                      return 0;
                  }
                  

                  特性 Python容器 C++ STL容器
                  类型系统 动态类型,容器可包含任意类型 静态类型,容器元素类型固定
                  内存管理 自动垃圾回收 手动或RAII管理
                  性能控制 有限,依赖解释器优化 细粒度控制,可优化到硬件级
                  转换灵活性 灵活,自动类型转换 严格,需要显式转换
                  迭代方式 简单for循环 迭代器模式
                  算法集成 内置方法较少,依赖标准库函数 丰富的算法库,与容器深度集成
                  并发安全 GIL限制,部分操作原子 默认非线程安全,需要外部同步
                  内存布局 隐藏细节 明确控制(连续/链式)

                  1. 选择合适容器

                    • vector:默认选择,缓存友好
                    • list/forward_list:频繁插入删除
                    • deque:两端操作频繁
                    • set/map:需要排序或快速查找
                    • unordered_set/unordered_map:只需要快速查找,不关心顺序
                  2. 性能优化

                    • 预分配vector内存
                    • 使用emplace代替insert
                    • 优先使用算法库而非手写循环
                    • 考虑使用移动语义
                  3. 现代C++特性

                    • 使用范围for循环(C++11)
                    • 使用结构化绑定(C++17)
                    • 使用概念和范围(C++20)
                    • 使用智能指针管理资源
                  4. 错误处理

                    • 使用at()进行边界检查
                    • 检查迭代器有效性
                    • 使用异常处理资源错误

                  C++容器系统提供了强大的功能和性能控制,但需要更多的类型安全和内存管理考虑。掌握这些工具可以编写出高效、可靠的C++代码。

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