Beautiful Soup 4: How to replace a tag with text and another tag?

Question

I want to replace a tag with another tag and put the contents of the old tag before the new one. For example:

I want to change this:

Answer 1

The idea is to find every span tag with id attribute (span[id] CSS Selector), use insert_after() to insert a sup tag after it and unwrap() to replace the tag with it's contents:

from bs4 import BeautifulSoup

data = """


This is the first paragraph
This is the second paragraph


"""

soup = BeautifulSoup(data)
for span in soup.select('span[id]'):
    # insert sup tag after the span
    sup = soup.new_tag('sup')
    sup.string = span['id']
    span.insert_after(sup)

    # replace the span tag with it's contents
    span.unwrap()

print soup

Prints:

This is the first1 paragraph
This is the second2 paragraph