Decorator将赢得工作：＆＃x27; nontype＆＃x27;对象不可呼应

发布于 2025-02-11 15:38:01 字数 419 浏览 3 评论 0原文

import numpy as np

def multi_print(n):
    def decorator(func):
        def wrapper(*args, **kwargs):
            for z in np.arange(n):
                print(func(*args))

@multi_print(2)   
def if_num(x):
    if x == 1:
        return 'abc'
    else:
        return 'def'

if_num(3)

我正在尝试使用装饰者如何与功能进行互动。当我运行此代码块时，我会得到一个'nontype'对象是不可callable错误。不确定为什么。我希望上述代码将两次打印“ DEF”。

原文

import numpy as np

def multi_print(n):
    def decorator(func):
        def wrapper(*args, **kwargs):
            for z in np.arange(n):
                print(func(*args))

@multi_print(2)   
def if_num(x):
    if x == 1:
        return 'abc'
    else:
        return 'def'

if_num(3)

I am trying to just play around with how decorators interact with functions. When I run this block of code, I get a 'NoneType' object is not callable error. Wasn't sure why. I would expect the above code to print "def" two times.

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南冥有猫 2025-02-18 15:38:01

您的装饰师和包装纸什么都不会返回。带有争论的装饰符应返回装饰器，并且装饰器应返回包装功能。修复：

import numpy as np

def multi_print(n):
    def decorator(func):
        def wrapper(*args, **kwargs):
            for z in np.arange(n):
                print(func(*args, **kwargs)) # should pass on kwargs, too
        return wrapper
    return decorator

@multi_print(2)   
def if_num(x):
    if x == 1:
        return 'abc'
    else:
        return 'def'

if_num(3)

输出：

def
def

Your decorator and wrapper don't return anything. A decorator with arguments should return a decorator, and the decorator should return the wrapped function. The fix:

import numpy as np

def multi_print(n):
    def decorator(func):
        def wrapper(*args, **kwargs):
            for z in np.arange(n):
                print(func(*args, **kwargs)) # should pass on kwargs, too
        return wrapper
    return decorator

@multi_print(2)   
def if_num(x):
    if x == 1:
        return 'abc'
    else:
        return 'def'

if_num(3)

Output: