regex – How can I find all matches to a regular expression in Python?

The Question :

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In a program I’m writing I have Python use the re.search() function to find matches in a block of text and print the results. However, the program exits once it finds the first match in the block of text.

How do I do this repeatedly where the program doesn’t stop until ALL matches have been found? Is there a separate function to do this?

The Question Comments :
  • Recursive REs are a different beast. You want to repeat the search.

The Answer 1

614 people think this answer is useful

Use re.findall or re.finditer instead.

re.findall(pattern, string) returns a list of matching strings.

re.finditer(pattern, string) returns an iterator over MatchObject objects.

Example:

re.findall( r'all (.*?) are', 'all cats are smarter than dogs, all dogs are dumber than cats')
# Output: ['cats', 'dogs']

[x.group() for x in re.finditer( r'all (.*?) are', 'all cats are smarter than dogs, all dogs are dumber than cats')]
# Output: ['all cats are', 'all dogs are']

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