Python基本类型提示详解 - 变量与容器类型标注指南

# 变量类型提示
variable_name: type = value

# 函数参数和返回值类型提示
def function_name(param1: type1, param2: type2) -> return_type:
    ...

# 容器类型提示（Python 3.9+ 内置泛型）
names: list[str] = ["Alice", "Bob"]
scores: dict[str, int] = {"Alice": 90}
point: tuple[int, int] = (1, 2)
unique_ids: set[int] = {1, 2, 3}

# 容器类型提示（typing 模块，兼容旧版本）
from typing import List, Dict, Tuple, Set
names: List[str] = ["Alice", "Bob"]
scores: Dict[str, int] = {"Alice": 90}
point: Tuple[int, int] = (1, 2)
unique_ids: Set[int] = {1, 2, 3}

# 变量类型提示
name: str = "Alice"
age: int = 30
height: float = 1.75
is_student: bool = False

print(f"姓名: {name}, 年龄: {age}, 身高: {height}m, 学生: {is_student}")

# 函数类型提示
def add(a: int, b: int) -> int:
    """两数相加"""
    return a + b

def greet(name: str, times: int = 1) -> str:
    """重复问候"""
    return (f"Hello, {name}! " * times).strip()

result = add(3, 5)
greeting = greet("Bob", 2)
print(f"3 + 5 = {result}")
print(greeting)

姓名: Alice, 年龄: 30, 身高: 1.75m, 学生: False
3 + 5 = 8
Hello, Bob! Hello, Bob!

from typing import List, Dict, Tuple, Set

# 列表类型提示
student_names: List[str] = ["Alice", "Bob", "Charlie"]
print(f"学生列表: {student_names}")

# 字典类型提示
grade_book: Dict[str, float] = {
    "Alice": 95.5,
    "Bob": 87.0,
    "Charlie": 92.3
}
print(f"成绩册: {grade_book}")

# 元组类型提示（固定长度）
coordinates: Tuple[float, float, float] = (1.0, 2.0, 3.0)
print(f"坐标: {coordinates}")

# 集合类型提示
unique_tags: Set[str] = {"python", "typing", "hints"}
print(f"标签: {unique_tags}")

# 变长元组
numbers: Tuple[int, ...] = (1, 2, 3, 4, 5)
print(f"数字: {numbers}")

学生列表: ['Alice', 'Bob', 'Charlie']
成绩册: {'Alice': 95.5, 'Bob': 87.0, 'Charlie': 92.3}
坐标: (1.0, 2.0, 3.0)
标签: {'python', 'typing', 'hints'}
数字: (1, 2, 3, 4, 5)

from typing import List, Dict, Tuple, Optional

# 嵌套容器类型
matrix: List[List[int]] = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
]
print(f"矩阵: {matrix}")

# 复杂字典结构
user_database: Dict[str, Dict[str, str]] = {
    "user001": {"name": "Alice", "email": "alice@example.com"},
    "user002": {"name": "Bob", "email": "bob@example.com"}
}
print(f"用户数据库: {user_database}")

# 函数中使用复杂类型
def find_student(
    records: Dict[str, List[Tuple[str, float]]],
    student_id: str
) -> Optional[List[Tuple[str, float]]]:
    """根据学号查找学生成绩记录"""
    return records.get(student_id)

# 使用
school_records: Dict[str, List[Tuple[str, float]]] = {
    "S001": [("数学", 95.0), ("英语", 88.5)],
    "S002": [("数学", 78.0), ("英语", 92.0)]
}

result = find_student(school_records, "S001")
print(f"S001 的成绩: {result}")

not_found = find_student(school_records, "S999")
print(f"S999 的成绩: {not_found}")

矩阵: [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
用户数据库: {'user001': {'name': 'Alice', 'email': 'alice@example.com'}, 'user002': {'name': 'Bob', 'email': 'bob@example.com'}}
S001 的成绩: [('数学', 95.0), ('英语', 88.5)]
S999 的成绩: None