How to grab numbers in the middle of a string? (Python)

Question

random string
this is 34 the string 3 that, i need 234
random string
random string
random string
random string

random string
this is 1 the string 34 that, i need 22
random string
random string
random string
random string

random string
this is 35 the string 55 that, i need 12
random string
random string
random string
random string

Within one string there are multiple lines. One of the lines is repeated but with different numbers each time. I was wondering how can I store the numbers in those lines. The numbers will always be in the same position in the line, but can be any number of digits.

Edit: The random strings could have numbers in them as well.

Answer 1

Use regular expressions:

>>> import re
>>> comp_re = re.compile('this is (\d+) the string (\d+) that, i need (\d+)')
>>> s = """random string
this is 34 the string 3 that, i need 234
random string
random string
random string
random string

random string
this is 1 the string 34 that, i need 22
random string
random string
random string
random string

random string
this is 35 the string 55 that, i need 12
random string
random string
random string
random string
"""
>>> comp_re.findall(s)
[('34', '3', '234'), ('1', '34', '22'), ('35', '55', '12')]

Answer 2

By using regular expressions

import re
s = """random string
this is 34 the string 3 that, i need 234
random string
random string
random string
"""
re.findall('this is (\d+) the string (\d+) that, i need (\d+)', s)