python函数参数类型校验-优快云博客

本文介绍了一个Python装饰器，用于实现函数参数类型的自动检查。通过使用inspect和functools模块，该装饰器可以在运行时验证传入参数是否符合预设的数据类型，有助于减少因类型错误导致的运行时异常。

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#!/usr/bin/python
# encoding:utf-8
from inspect import signature
from functools import wraps


def typeassert(*ty_args, **ty_kwargs):
    def decorate(func):
        # If in optimized mode, disable type checking
        if not __debug__:
            return func
        # Map function argument names to supplied types
        sig = signature(func)
        bound_types = sig.bind_partial(*ty_args, **ty_kwargs).arguments

        @wraps(func)
        def wrapper(*args, **kwargs):
            bound_values = sig.bind(*args, **kwargs)
            # Enforce type assertions across supplied arguments
            for name, value in bound_values.arguments.items():
                if name in bound_types:
                    if not isinstance(value, bound_types[name]):
                        raise TypeError(
                            'Argument {} must be {}'.format(name, bound_types[name])
                        )
            return func(*args, **kwargs)

        return wrapper

    return decorate


@typeassert(int, z=int)
def spam(x, y, z=42):
    return x, y, z


print(spam(1, 2, 3))
print(spam(1, 2, "4"))

输出：

(1, 2, 3)
Traceback (most recent call last):
File "D:/workerspace/python3_learning/test/atest10.py", line 39, in <module>
print(spam(1, 2, "4"))
File "D:/workerspace/python3_learning/test/atest10.py", line 24, in wrapper
'Argument {} must be {}'.format(name, bound_types[name])
TypeError: Argument z must be <class 'int'>

转载于:https://my.oschina.net/yves175/blog/1942220