Python: How to search a value in a log using identifier

Question

So I want to make a program that can grab a numerical value from a log (.txt). Each value is associated with a log identifier. So here is the contents of my log file (named test.txt):

Log:

ID        Key           Value_1 Value_2
f1     time (sec)       1000     2000
f2     # of people       20       31
f3   # tickets written   27       87

So I want to grab the value 27 from ID f3. Is there a way to do this? I have an idea using readlines() and looping line by line until the ID is found but not sure what to do from there. Here's what I have so far:

with open('test.txt') as f:
    data = f.readlines()

for line in data:
    if 'f3' in line:
        # Code to retrieve value 27

Answer 1

You can use regex

import re

with open('test.txt') as f:
    for line in f:
        if line[0:2] == "f3":
            print(re.search("\d+", line[2:]).group(0))

27

---

Regex is a string matching tool. The pattern \d+ tells regex to look for at least one digit. So Regex (re) searches line[2:] (2: skips the first 2 letters) and saves all matches (numbers). Then .group(0) fetches the first result. which is 27

Online demo