How to extract value of all classes in beautiful Soup - beautifulsoup

Question

I have a HTML file with a structure like this:
<p id="01">... EU legislation and the <em>monetary power</em> of the
<span class="institution" Wikidata="Q8901" name="European Central Bank">ECB</span>.</p>
<p id="02"><span class="person" Wikidata="Q563217">Guido Carli</span>, Governor of the
<span class="institution" Wikidata="Q806176">Bank of Italy</span> ...</p>
I need to have a Python dict like this:
{'institution': ['Q8901', 'Q806176'], 'person': ['Q563217']}
So I need to get the value of the class attribute of all span tags, along with their text. How can I do this with bs4?

Answer 1

Select your elements and iterate the ResultSet while appending the values to your dict. To extract the values of an attribute use .get(). Because class will give you a list pick yours by index or key.
Example
from bs4 import BeautifulSoup
html = '''
<p id="01">... EU legislation and the <em>monetary power</em> of the
<span class="institution" Wikidata="Q8901" name="European Central Bank">ECB</span>.</p>
<p id="02"><span class="person" Wikidata="Q563217">Guido Carli</span>, Governor of the
<span class="institution" Wikidata="Q806176">Bank of Italy</span> ...</p>
'''
soup = BeautifulSoup(html)
d = {
'institution':[],
'person':[]
}
for e in soup.select('span[wikidata]'):
d[e.get('class')[0]].append(e.get('wikidata'))
d
Output
{'institution': ['Q8901', 'Q806176'], 'person': ['Q563217']}

Answer 2

This is the way I solved my problem thanks to #HedgeHog.
from bs4 import BeautifulSoup
from collections import defaultdict
def capture_info(soup: 'BeautifulSoup') -> defaultdict:
info = defaultdict(list)
for i in soup.select('span[Wikidata]'):
info[i.get('class')[0]].append(i.get('wikidata'))
return info
html = '''
<p id="01">... EU legislation and the <em>monetary power</em> of the
<span class="institution" Wikidata="Q8901" name="European Central Bank">ECB</span>.</p>
<p id="02"><span class="person" Wikidata="Q563217">Guido Carli</span>, Governor of the
<span class="institution" Wikidata="Q806176">Bank of Italy</span> ...</p>
'''
soup = BeautifulSoup(html, 'html.parser')
info = capture_info(soup)
The output is:
{'institution': ['Q8901', 'Q806176'], 'person': ['Q563217']})