Python 类型提示 Type Hint

Python 3.5+ 支持类型提示，让代码更易维护。

1. 基本类型

def greet(name: str) -> str:
    return f"Hello, {name}"

def add(a: int, b: int) -> int:
    return a + b

2. 变量类型

# Python 3.6+
name: str = "Alice"
age: int = 25
scores: list = [1, 2, 3]

3. 复杂类型

from typing import List, Dict, Tuple, Optional, Union

# 列表
names: List[str] = ["Alice", "Bob"]

# 字典
scores: Dict[str, int] = {"Alice": 90}

# 可选
age: Optional[int] = None

# 联合类型
value: Union[int, str] = 10

4. 类型别名

User = Dict[str, Union[str, int]]
users: List[User] = []

5. 运行检查

# 安装 mypy
# pip install mypy

# 运行检查
# mypy your_file.py

类型提示让代码更可靠。