Python BeautifulSoup写入HTML标签时转义问题求助

问题场景 #

使用以下代码操作本地HTML文件时：

from bs4 import BeautifulSoup

soup = BeautifulSoup(open('input.html', encoding="utf-8"), 'lxml') #local html file
soup.select_one("#target").clear()
soup.select_one("#target").insert(0, "<h1>Heading</h1>")

with open("output.html", "w", encoding="utf-8") as file:
  file.write(str(soup))

执行后插入的内容被转为字符串实体，结果如下：

<div id="target">&lt;h1&gt;Heading&lt;/h1&gt;</div>

期望得到实际的HTML标签：

<div id="target"><h1>Heading</h1></div>

解决方案 #

方法1：解析HTML片段后插入 #

将HTML字符串用BeautifulSoup解析为标签对象，再插入目标容器：

from bs4 import BeautifulSoup

soup = BeautifulSoup(open('input.html', encoding="utf-8"), 'lxml')
target = soup.select_one("#target")
target.clear()
# 解析HTML片段生成可插入的标签结构
new_content = BeautifulSoup("<h1>Heading</h1>", 'lxml')
target.append(new_content)

with open("output.html", "w", encoding="utf-8") as file:
    file.write(str(soup))

方法2：手动创建标签并添加 #

通过new_tag方法创建指定标签，设置内容后插入：

from bs4 import BeautifulSoup

soup = BeautifulSoup(open('input.html', encoding="utf-8"), 'lxml')
target = soup.select_one("#target")
target.clear()
# 创建h1标签
h1_tag = soup.new_tag("h1")
# 设置标签文本内容
h1_tag.string = "Heading"
# 插入到目标容器的开头
target.insert(0, h1_tag)

with open("output.html", "w", encoding="utf-8") as file:
    file.write(str(soup))

原因说明 #

直接向insert方法传入字符串时，BeautifulSoup会将其视为纯文本，自动转义<、>等HTML特殊字符。只有传入BeautifulSoup解析后的Tag对象或手动创建的标签实例，才会被识别为HTML元素插入到文档中。

内容的提问来源于stack exchange，提问作者aboutjquery