regex - Repeatedly extract a line between two delimiters in a text file, Python

Question

I have a text file in the following format:

DELIMITER1
extract me
extract me
extract me
DELIMITER2

I'd like to extract every block of extract mes between DELIMITER1 and DELIMITER2 in the .txt file

This is my current, non-performing code:

import re
def GetTheSentences(file):
     fileContents =  open(file)
     start_rx = re.compile('DELIMITER')
     end_rx = re.compile('DELIMITER2')

     line_iterator = iter(fileContents)
     start = False
     for line in line_iterator:
           if re.findall(start_rx, line):

                start = True
                break
      while start:
           next_line = next(line_iterator)
           if re.findall(end_rx, next_line):
                break

           print next_line

           continue
      line_iterator.next()

Any ideas?

Answer 1

You can simplify this to one regular expression using re.S, the DOTALL flag.

import re
def GetTheSentences(infile):
     with open(infile) as fp:
         for result in re.findall('DELIMITER1(.*?)DELIMITER2', fp.read(), re.S):
             print result
# extract me
# extract me
# extract me

This also makes use of the non-greedy operator .*?, so multiple non-overlapping blocks of DELIMITER1-DELIMITER2 pairs will all be found.