Python regex help :)?

Question

I'm trying to match, last letter in string 'onlin' as any and then replace it if it matches with word offline. No luck. Please give advice, cheers.

import mitmproxy
import re

def response(flow):
    old = b'Onlin\w{1}'
    new = b'Offline'
    flow.response.content = flow.response.content.replace(old, new)

Does it work if you remove that `’` character in `Onlin\w{1}’`? — Aran-Fey, May 26 '18 at 13:13
It's not clear what you're asking. Can you explain what the expected output is? — rst-2cv, May 26 '18 at 13:16
In flow.response.content.replace value of variable 'old' is replace by value of the variable 'new'. Im trying to use regex to match value of variable old with the last character as wildcard. But it doesn't work. Basically 'onlin' + [a-z, 0-9] — Matas Petkevičius, May 26 '18 at 13:20

Mišo · Accepted Answer · 2018-05-26T13:30:48.950

5

I guess you are using the wrong function for replacement. Try re.sub.

def response(flow):
    old = b'Onlin\w'
    new = b'Offline'
    # https://docs.python.org/3/library/re.html#re.sub
    flow.response.content = re.sub(old, new, flow.response.content)

edited May 26 '18 at 13:30

answered May 26 '18 at 13:19

Mišo

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Works very well, cheers, I'm quite new to this – Matas Petkevičius May 26 '18 at 13:26

score 2 · Answer 2 · answered May 26 '18 at 13:22

str.replace() does not recognize regular expressions.

To perform a substitution using a regular expression, use re.sub().

The pattern Onlin. matches any string that starts with Onlin and ends with any character.

import re

old = re.compile('Onlin.')

def response(flow):
    new = 'Offline'
    flow.response.content = old.sub(new, flow.response.content)

Example:

>>> old = re.compile("Onlin.")
>>> old.sub(new, "Onlin Onlina Online")
'offlineoffline offline'

This did not work, but thank You for your time. – Matas Petkevičius May 26 '18 at 13:30 — Matas Petkevičius, May 26 '18 at 13:30

Python regex help :)?

2 Answers2