如何将修饰器中的变量传递给修饰函数中的函数参数？ [英] How can I pass a variable in a decorator to function's argument in a decorated function?

问题描述

我正在学习Python。希望有人指出我正确的方法。

这是我想在下面做的事情：

I am in progress to learn Python. Hopefully someone points me to correct way.
This is what I'd like to do below:

def decorate(function):
    def wrap_function(*args, **kwargs):
        str = 'Hello!'  # This is what I want
        return function(*args, **kwargs)
    return wrap_function

@decorate
def print_message():
    # I'd like to pass 'str' as mentioned above
    # to any functions' argument like below:
    print(str)  # 'str' is same as above

有什么主意吗？

推荐答案

您不能将其作为自己的名称传递，但可以将其添加到关键字中。 / p>

You can't pass it as its own name, but you can add it to the keywords.

def decorate(function):
    def wrap_function(*args, **kwargs):
        kwargs['str'] = 'Hello!'
        return function(*args, **kwargs)
    return wrap_function

@decorate
def print_message(*args, **kwargs):
    print(kwargs['str'])

您也可以命名自己的参数：

Alternatively you can name its own argument:

def decorate(function):
    def wrap_function(*args, **kwargs):
        str = 'Hello!'
        return function(str, *args, **kwargs)
    return wrap_function

@decorate
def print_message(str, *args, **kwargs):
    print(str)

类方法：

def decorate(function):
    def wrap_function(*args, **kwargs):
        str = 'Hello!'
        args.insert(1, str)
        return function(*args, **kwargs)
    return wrap_function

class Printer:
    @decorate
    def print_message(self, str, *args, **kwargs):
        print(str)

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