使用BeautifulSoup计算函数中的xml元素

Question

我经常使用len(find_all("some_element")来计算xml文件中的实体数量。我试图建立一个函数，但它不工作/它总是给我& None"

XML文件:

<parent>
<some>
<child>text</child>
<child>text</child>
<child>text</child>
</some>
</parent>

我的python代码:

def return_len(para1,para2): # doesn't work
if bool(suppe.para1): # the element isn't always present in the xml
return len(suppe.para1.find_all(para2))
def return_len1(): # does work
if bool(suppe.some):
return len(suppe.some.find_all("child"))
print(return_len("some","child")) # doesnt work
print(return_len1()) # does work

我必须如何修改我的函数return_len得到工作/我错了什么?

Answer 1

你可以这样做。

from bs4 import BeautifulSoup
s = """<parent>
<some>
<child>text</child>
<child>text</child>
<child>text</child>
</some>
</parent>    
"""
soup = BeautifulSoup(s, 'xml')
def return_len(para1,para2,soup):
print(f'No. of <{para2}> tags inside <{para1}> tag.')
temp = soup.find(para1)
if temp:
return len(temp.find_all(para2))
print(return_len('some', 'child', soup))
print(return_len('parent', 'some', soup))

No. of <child> tags inside <some> tag.
3
No. of <some> tags inside <parent> tag.
1

Answer 2

没有任何外部库-参见下面的

import xml.etree.ElementTree as ET

xml = '''<parent>
<some>
<child>text</child>
<child>text</child>
<child>text</child>
</some>
</parent>'''
root = ET.fromstring(xml)
print(f'Number of child elements is {len(root.findall(".//child"))}') 

输出

Number of child elements is 3