Regular Expressions 101

Community Patterns

Using a Non-Capturing Group (regex + python)

1

Regular Expression
Python

r"
b?(?:.a)*
"
gm

Description

Using a Non-capturing Group: regex + python

This question was asked on stackoverflow and it appeared that the best way to match the expression will be to use a non-capturing group.

Suppose the text is 'bcacaca' and you want to match any pattern where you have an optional b followed by zero or more .a pattern.

Here is an example. For more details, see this on regex101.

import re

## Define text and pattern
text = 'bcacaca dcaca dbcaca'
pattern = 'b?(?:.a)*'

## Evaluate regex
result = re.findall(pattern, text)
# output
# ['bcacaca', '', '', 'caca', '', '', 'bcaca', '']

## Drop empty strings from result
result = list(filter(None, result))
# output
# ['bcacaca', 'caca', 'bcaca']
Submitted by anonymous - 4 years ago