Python3.2中用soup.findAll获取class值及多class匹配问题排查

Let's tackle your two BeautifulSoup questions one by one—these are common snags when working with HTML parsing, so let's break them down clearly:

First, make sure you're using BeautifulSoup 4 (bs4)—it’s fully compatible with Python 3.2 and the standard for this kind of work. Here’s how to do it:

• Use findAll() (or its alias find_all()—they work identically) to locate elements by class. Note we use class_ (with an underscore) instead of plain class because class is a reserved keyword in Python.
• Once you’ve fetched the elements, access the class attribute like a dictionary key: elem['class']. This returns a list of strings, since HTML elements can have multiple classes.

Example code to illustrate:

from bs4 import BeautifulSoup

# Sample HTML content
html = '''
<div class="basic-class">Test Element 1</div>
<div class="multi class group">Test Element 2</div>
'''

# Initialize the soup object
soup = BeautifulSoup(html, 'html.parser')

# Find all divs with "basic-class"
basic_elements = soup.findAll('div', class_='basic-class')
for elem in basic_elements:
    print(f"Class list: {elem['class']}")  # Output: ['basic-class']

# Find all divs containing "class" in their classes
multi_elements = soup.findAll('div', class_='class')
for elem in multi_elements:
    print(f"Class list: {elem['class']}")  # Output: ['multi', 'class', 'group']

Your custom match_class() approach failed because BeautifulSoup parses the class attribute into a list of individual class names, not a single space-separated string. Comparing against a full string like "col-lg-3 col-md-4 col-sm-6 bt-product-list" won’t match since the element’s class value is stored as a list.

You have two simple, reliable fixes:

Option 1: Use BeautifulSoup's built-in multi-class support #

BeautifulSoup lets you pass a list of class names to class_, and it will match elements that have all those classes (order doesn’t matter):

# Target classes as a list
target_classes = ['col-lg-3', 'col-md-4', 'col-sm-6', 'bt-product-list']
# Find divs with all these classes
elements = soup.findAll('div', class_=target_classes)

Option 2: Fix your custom match_class function #

If you prefer using a custom function, update it to check that every target class exists in the element’s class list:

def match_class(target_classes):
    def check_element(elem):
        # Get the element's class list (empty list if no class attribute exists)
        elem_classes = elem.get('class', [])
        # Return True only if all target classes are present
        return all(cls in elem_classes for cls in target_classes)
    return check_element

# Now use the function correctly
elements = soup.findAll(match_class(['col-lg-3', 'col-md-4', 'col-sm-6', 'bt-product-list']))

Either method will correctly locate the elements you’re targeting.

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