BeautifulSoup XML：通过兄弟元素的文本查找元素答案

【问题标题】：BeautifulSoup XML: finding elements by sibling element's textBeautifulSoup XML：通过兄弟元素的文本查找元素
【发布时间】：2018-12-25 23:35:43
【问题描述】：

在following example 中，我想查找价格为 8.99 的所有书名。换句话说，我想根据兄弟元素的文本来查找元素的文本。

from bs4 import BeautifulSoup
XML = """<?xml version="1.0">
<library>
    <book>
        <title>The Cat in the Hat</title>
        <author>Dr. Seuss</author>
        <price>7.35</price>
    </book>
    <book>
        <title>Ender's Game</title>
        <author>Orson Scott Card</author>
        <price>8.99</price>
    </book>
    <book>
        <title>Prey</title>
        <author>Michael Crichton</author>
        <price>8.99</price>
    </book>
</library>
"""
soup = BeautifulSoup(XML, "xml")

令人惊讶的是，查询soup.find({"price": 8.99}).parent 会返回错误的书：

<book>
<title>The Cat in the Hat</title>
<author>Dr. Seuss</author>
<price>7.35</price>
</book>

更新

查询[x.parent.find("title").text for x in soup.find_all("price", text = 8.99)] 返回列表["Ender's Game", "Prey"]，这正是我想要的。但这是最好的方法吗？

【问题讨论】：

标签： python xml beautifulsoup xml-parsing

【解决方案1】：

您可以使用find_previous_sibling()。

from bs4 import BeautifulSoup
XML = """<?xml version="1.0">
<library>
    <book>
        <title>The Cat in the Hat</title>
        <author>Dr. Seuss</author>
        <price>7.35</price>
    </book>
    <book>
        <title>Ender's Game</title>
        <author>Orson Scott Card</author>
        <price>8.99</price>
    </book>
    <book>
        <title>Prey</title>
        <author>Michael Crichton</author>
        <price>8.99</price>
    </book>
</library>
"""
soup = BeautifulSoup(XML, "xml")

prices = soup.find_all("price", text=8.99)
for price in prices:
    title = price.find_previous_sibling('title')
    print(title)

# and with list comprehension
titles = [price.find_previous_sibling('title').text for price in prices]                                                                                                                                                        
print(titles)

输出

<title>Ender's Game</title>
<title>Prey</title>

# List comprehension
["Ender's Game", 'Prey']

【讨论】：