Create RegEx to find such strings?

Question

I am new to RegEx in python. I have created a RegEx formula which should find some special string from text but it is not working as exprected;

def find_short_url(str_field):
    search_string = r"moourl.com|ow.ly|goo.gl|polr.me|su.pr|bit.ly|is.gd|tinyurl.com|buff.ly|bit.do|adf.ly"
    search_string = re.search(search_string, str(str_field))
    result = search_string.group(0) if search_string else None
    return result

It should find all the URL shortner from a text. But the su.pr is detecting as surpr from the text. Is there any way to fix it?

find_short_url("It is a surprise that it is ...")

output

'surpr'

It can affect other shortner too. Still scratching my head.

Escape the dot to make it match a literal dot. – Wiktor Stribiżew May 22 '19 at 18:03 — Wiktor Stribiżew, May 22 '19 at 18:03

Bohemian · Accepted Answer · 2019-05-22T18:12:56.887

0

Escape the dots:

search_string = r"moourl\.com|ow\.ly|goo\.gl|polr\.me|su\.pr|bit\.ly|is\.gd|tinyurl\.com|buff\.ly|bit\.do|adf\.ly"

In regex, a dot matches any character. Escaping them makes them match a literal dot.

edited May 22 '19 at 18:12

answered May 22 '19 at 18:03

Bohemian

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But now it can not find the words. `find_short_url("It is a surprise that it is ... http://goo.gl")` .Return nothing. – DataPsycho May 22 '19 at 18:09
No, Bohemian, `r'a\\.b'` matches ``a\bc`` as `r'...'` is a raw string literal where backslashes are treated as literals. – Wiktor Stribiżew May 22 '19 at 18:09
Ok. Without raw string except r it works fine. – DataPsycho May 22 '19 at 18:11
@Wiktor so `r"a\.b"` then. see edit. – Bohemian May 22 '19 at 18:13
I have found also `abc[.]com` escape the dot character, which makes it a character class i guess. – DataPsycho May 23 '19 at 12:31
1

@DataPsycho agreed. the good thing about `[.]` is you don't have to know how to delimit characters in the context of the combination of the app language and the flavor of regex it uses; which also means the regex is portable. – Bohemian May 23 '19 at 16:04

Create RegEx to find such strings?

1 Answers1