Python 基础语法案例

下面这段代码可以直接复制到 .py 文件中运行，覆盖函数进阶、异常、文件操作和类型注解。

from dataclasses import dataclass
from pathlib import Path
from tempfile import TemporaryDirectory
 
 
def total(*numbers):
    return sum(numbers)
 
 
def build_profile(name, **extra):
    return {"name": name, **extra}
 
 
def make_multiplier(factor):
    def multiply(value):
        return value * factor
 
    return multiply
 
 
def divide(a, b):
    if b == 0:
        raise ValueError("b must not be zero")
    return a / b
 
 
@dataclass
class Student:
    name: str
    score: int
 
 
def passed(students: list[Student], line: int = 60) -> list[str]:
    return [student.name for student in students if student.score >= line]
 
 
def file_case():
    with TemporaryDirectory() as temp_dir:
        path = Path(temp_dir) / "demo.txt"
        path.write_text("hello\npython\n", encoding="utf-8")
        with path.open("a", encoding="utf-8") as file:
            file.write("file demo\n")
        print(path.read_text(encoding="utf-8"))
 
 
def main():
    print("var args:", total(1, 2, 3))
    print("kwargs:", build_profile("Tom", age=20, city="Beijing"))
 
    double = make_multiplier(2)
    print("closure:", double(10))
 
    for value in [2, 0]:
        try:
            print("divide:", divide(10, value))
        except ValueError as error:
            print("handled:", error)
 
    students = [Student("Tom", 80), Student("Lucy", 95), Student("Jack", 50)]
    print("passed:", passed(students))
 
    file_case()
 
 
if __name__ == "__main__":
    main()