BS4 replace_with 结果不再在树中

Question

我需要替换 html 文档中的多个单词。 Atm 我通过为每次替换调用一次 replace_with 来做到这一点。在 NavigableString 上调用 replace_with 两次会导致 ValueError（参见下面的示例），导致被替换的元素不再在树中。

小例子

#!/usr/bin/env python3
from bs4 import BeautifulSoup
import re
def test1():
  html = \
  '''
    Identify
  '''
  soup = BeautifulSoup(html,features="html.parser")
  for txt in soup.findAll(text=True):
    if re.search('identify',txt,re.I) and txt.parent.name != 'a':
      newtext = re.sub('identify', '<a href="test.html"> test </a>', txt.lower())
      txt.replace_with(BeautifulSoup(newtext, features="html.parser"))
      txt.replace_with(BeautifulSoup(newtext, features="html.parser"))
      # I called it twice here to make the code as small as possible.
      # Usually it would be a different newtext ..
      # which was created using the replaced txt looking for a different word to replace.        

  return soup
print(test1())

预期结果：

The txt is == newstring

结果：

ValueError: Cannot replace one element with another when the element to be replaced is not
part of the tree.

一个简单的解决方案就是修补新字符串，最后只一次全部替换，但我想了解当前的现象。

Answer 1

第一个 txt.replace_with(...) 从文档树 (doc) 中删除 NavigableString（这里存储在变量 txt 中）。这有效地将txt.parent 设置为None

第二个txt.replace_with(...) 查看parent 属性，找到None（因为txt 已从树中删除）并引发ValueError。

正如您在问题末尾所说，一种解决方案是只使用一次.replace_with()：

import re
from bs4 import BeautifulSoup

def test1():
    html = \
    '''
    word1 word2 word3 word4
    '''
    soup = BeautifulSoup(html,features="html.parser")

    to_delete = []
    for txt in soup.findAll(text=True):
        if re.search('word1', txt, flags=re.I) and txt.parent.name != 'a':
            newtext = re.sub('word1', '<a href="test.html"> test1 </a>', txt.lower())
            
            # ...some computations

            newtext = re.sub('word3', '<a href="test.html"> test2 </a>', newtext)

            # ...some more computations

            # and at the end, replce txt only once:
            txt.replace_with(BeautifulSoup(newtext, features="html.parser"))

    return soup
print(test1())

打印：

<a href="test.html"> test1 </a> word2 <a href="test.html"> test2 </a> word4