How to Beautiful Soup (bs4) match just one, and only one, css class

Question

I am using following code to match all div that have CSS class \"ad_item\".

soup.find_all(\'div\',class_=\"ad_item\")

problem that I have i

Answer 1

You can pass a lambda functions to find and find_all methods.

soup.find_all(lambda x:
    x.name == 'div' and
    'ad_item' in x.get('class', []) and
    not 'ad_ex_item' in x['class']
)

The x.get('class', []) will avoid KeyError exceptions for div tags without class attribute.

If you need to exclude more than only one class you can substitute the last condition with:

    not any(c in x['class'] for c in {'ad_ex_item', 'another_class'})

And if you want to exclude exactly some classes you can use:

   not all(c in x['class'] for c in {'ad_ex_item', 'another_class'})