Python列表操作示例

# 列表创建
numbers = [1, 2, 3, 4, 5]
mixed = [1, "Python", 3.14, True]
empty = []
repeated = [0] * 5  # [0, 0, 0, 0, 0]

# 列表访问
first = numbers[0]      # 获取第一个元素
last = numbers[-1]      # 获取最后一个元素
sub_list = numbers[1:4] # 切片获取子列表 [2, 3, 4]

# 列表修改
numbers[0] = 10        # 修改单个元素
numbers[1:4] = [20, 30, 40]  # 修改多个元素
numbers.append(6)      # 添加元素到末尾
numbers.insert(0, 0)   # 在指定位置插入元素
                

# 添加和删除元素
fruits = ["苹果", "香蕉", "橙子"]
fruits.append("葡萄")     # 添加到末尾
fruits.insert(1, "梨")    # 在指定位置插入
fruits.extend(["草莓", "樱桃"])  # 扩展列表

removed = fruits.pop()    # 删除并返回最后一个元素
fruits.pop(0)            # 删除并返回指定位置的元素
fruits.remove("香蕉")     # 删除第一个匹配的元素

# 查找和计数
index = fruits.index("橙子")  # 查找元素位置
count = fruits.count("苹果")  # 统计元素出现次数

# 排序和反转
numbers = [3, 1, 4, 1, 5, 9, 2, 6]
numbers.sort()           # 升序排序
numbers.sort(reverse=True)  # 降序排序
numbers.reverse()        # 反转列表
                

# 基本列表推导式
squares = [x**2 for x in range(10)]  # 生成平方数列表
evens = [x for x in range(10) if x % 2 == 0]  # 生成偶数列表

# 嵌套列表推导式
matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
flattened = [x for row in matrix for x in row]  # 展平列表

# 条件列表推导式
numbers = [-4, -2, 0, 2, 4]
abs_values = [abs(x) for x in numbers]  # 绝对值列表
pos_neg = ["正" if x > 0 else "负" if x < 0 else "零" for x in numbers]

# 字符处理示例
words = ["hello", "world", "python"]
upper_words = [word.upper() for word in words]  # 转换为大写
lengths = [len(word) for word in words]         # 计算长度
                

# 列表去重
def remove_duplicates(lst):
    return list(dict.fromkeys(lst))

# 列表分组
def group_by_length(words):
    groups = {}
    for word in words:
        length = len(word)
        if length not in groups:
            groups[length] = []
        groups[length].append(word)
    return groups

# 列表过滤
def filter_positive(numbers):
    return [num for num in numbers if num > 0]

# 列表交集和并集
def list_operations(list1, list2):
    intersection = list(set(list1) & set(list2))
    union = list(set(list1) | set(list2))
    return intersection, union

# 移动零元素
def move_zeros(lst):
    non_zeros = [x for x in lst if x != 0]
    zeros = [0] * (len(lst) - len(non_zeros))
    return non_zeros + zeros