Python re.findall from file

Question

I am trying to extract all of the text between two keywords in a text file. The keywords appear multiple times in the file, so I will have multiple blocks of good text.

The input.txt file is this:

bad bad keyword1 GOOD DATA keyword2 bad
bad bad bad keyword1 MORE 
GOOD DATA keyword2 bad bad 

This is not working:

import re

f = open('input.txt', 'r')
trim = re.findall('keyword1(.+?)keyword2', f.read())
print trim

It returns an empty list:

[]

Answer 1

If you want to grab all the data you should use re.DOTALL flag:

trim = re.findall('keyword1(.+?)keyword2', f.read(), re.DOTALL)

Usually the dot character means to get all chars but \n. With the DOTALL attribute the engine also matches \n for the dot character.

Output:

[' GOOD DATA ', ' MORE \nGOOD DATA ']

Answer 2

import re

s = "bad bad keyword1 GOOD DATA " \
    "keyword2 bad bad bad bad " \
    "keyword1 MORE GOOD DATA " \
    "keyword2 bad bad"

for i in re.findall('keyword1(.*?)keyword2', s, re.DOTALL):
    print(i)