Python extract pattern matches

Question

Python 2.7.1 I am trying to use python regular expression to extract words inside of a pattern

I have some string that looks like this

someline abc
s         


        

Answer 1

It seems like you're actually trying to extract a name vice simply find a match. If this is the case, having span indexes for your match is helpful and I'd recommend using re.finditer. As a shortcut, you know the name part of your regex is length 5 and the is valid is length 9, so you can slice the matching text to extract the name.

Note - In your example, it looks like s is string with line breaks, so that's what's assumed below.

## covert s to list of strings separated by line:
s2 = s.splitlines()

## find matches by line: 
for i, j in enumerate(s2):
    matches = re.finditer("name (.*) is valid", j)
    ## ignore lines without a match
    if matches:
        ## loop through match group elements
        for k in matches:
            ## get text
            match_txt = k.group(0)
            ## get line span
            match_span = k.span(0)
            ## extract username
            my_user_name = match_txt[5:-9]
            ## compare with original text
            print(f'Extracted Username: {my_user_name} - found on line {i}')
            print('Match Text:', match_txt)

Answer 2

Maybe that's a bit shorter and easier to understand:

import re
text = '... someline abc... someother line... name my_user_name is valid.. some more lines'
>>> re.search('name (.*) is valid', text).group(1)
'my_user_name'

Answer 3

You want a capture group.

p = re.compile("name (.*) is valid", re.flags) # parentheses for capture groups
print p.match(s).groups() # This gives you a tuple of your matches.