Python regex to strip out numbers attached to non-numbers

Asked Jul 31 '18 at 18:51

Active Jul 31 '18 at 18:51

Viewed 25 times

So I am trying to develop an app that requires a feature where it's able to detect numbers in a string that are not attached to letters.

Currently, this is the regex sequence I am using

foundNumber = bool(re.findall(r'\d+(?:,\d+)?', "I have 10 cats"))

For example, if we execute the above line, foundNumber = true, which is what I want.

But when I have this string:

foundNumber = bool(re.findall(r'\d+(?:,\d+)?', "I use 3D modeling."))

The regex sequence goes "Hey! I found a 3!" Whereas it's a false positive. foundNumber = true, whereas it should equal false.

Lastly, if I have this sequence:

foundNumber = bool(re.findall(r'\d+(?:,\d+)?', "I have 10 cats and I love 3D modeling"))

I should get a true value back since I still have 10 cats.

Can someone help me with my regex? I'm a beginner with regex, so any help would be appreciated, thanks!!!

asked Jul 31 '18 at 18:51

Shafiq Mohammed

`r'\b\d+(?:,\d+)?\b'` – Wiktor Stribiżew Jul 31 '18 at 18:54
Here is a useful cheat-sheet: https://www.debuggex.com/cheatsheet/regex/python. Hint: look at the 'word boundary', .i.e. `\b` – Sam Jul 31 '18 at 18:57
Perhaps the pattern should change the last question mark to an asterisk. Maybe OP wants to check numbers into the millions. `r'\b\d+(?:,\d+)*\b'` – Sunny Patel Jul 31 '18 at 18:58
You can probably use [`re.search()`](https://docs.python.org/2/library/re.html#re.search) instead and check if the match exists. – Sunny Patel Jul 31 '18 at 19:00
@WiktorStribiżew That works, thank you! – Shafiq Mohammed Jul 31 '18 at 19:08
@Sam that's a really useful cheat sheet, much appreciated! :) – Shafiq Mohammed Jul 31 '18 at 19:09

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