*作为python中的参数是什么意思?

2022-01-21 00:00:00 python arguments parameters

问题描述

我正在浏览 这个代码文件 然后我找到了这个类:

I was browsing through this file of code and then I found this class:

class StreamPlaylistEntry(BasePlaylistEntry):
def __init__(self, playlist, url, title, *, destination=None, **meta):
    super().__init__()

我知道参数前面的星号表示它是任意数量的参数的列表，但是星号本身是什么意思?

I know that an asterisk in front of a parameter means it's a list of an arbitrary number of arguments, but what does the asterisk by itself mean?

解决方案

这意味着后面的所有参数都是关键字.正如 官方词汇表中所说的 parameter:

It means all arguments afterwards are keyword-only. As said in the official glossary under the word parameter:

  • keyword-only: 指定一个只能由关键词.仅关键字参数可以通过包含单个var-positional 参数或裸 * 的参数列表中的前面的函数定义，例如 kw_only1 和 kw_only2 在以下:

  • keyword-only: specifies an argument that can be supplied only by keyword. Keyword-only parameters can be defined by including a single var-positional parameter or bare * in the parameter list of the function definition before them, for example kw_only1 and kw_only2 in the following:

def func(arg, *, kw_only1, kw_only2): ...

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