CSS组合器周围的空格是否真的是可选的 [英] Are spaces around CSS combinators are really optional

问题描述

在BeautifulSoup中将CSS选择器与轴组合器一起使用时，我有些困惑.下面是简单的代码来说明我的意思:

I'm a bit confused by using CSS selectors with axis combinators in BeautifulSoup. Below is the simple code to illustrate what I mean:

from bs4 import BeautifulSoup as bs
import requests

response = requests.get('https://stackoverflow.com/questions/tagged/python')
soup = bs(response.text)

print(len(soup.select('#mainbar > div'))) 

返回6个孩子...但是

print(len(soup.select('#mainbar>div')))

返回0个孩子...

与'#mainbar ~ div'(发现1个兄弟姐妹)和#mainbar~div'(没有发现任何东西)相同

The same with '#mainbar ~ div' (found 1 sibling) and #mainbar~div' (found nothing)

在文档中，这些空格是可选的，但在实际上，对于相同的选择器，我使用BeautifulSoup获得了不同的输出(我认为)

From documentation those spaces are optional, but in fact I got different output with BeautifulSoup for the same selectors (as I thought)

是bs4错误还是这种行为取决于CSS版本或其他?

So is it bs4 bug or this behavior depends on version of CSS or something else?

推荐答案

在此处确认为错误:从CSS角度来看，选择器可以使用/不使用.

The selector, from a CSS perspective is fine with/without.

我会看看是否可以找到进一步的证据.

I will see if I can find further evidence.

报告错误的个人指出:

据我所知，问题在于由于代码仅在执行 shlex.split，它不会将div，>和span分开对待 实体是>两侧的空白.

The issue, as far as I see, is that since the code is only doing a shlex.split, it doesn't treat div, >, and span as separate entities is a space is left out on either side of >.

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