Regex to remove repeated character pattern in a string

Question

I have a string that may have a repeated character pattern, e.g.

\'xyzzyxxyzzyxxyzzyx\'

I need to write a regex that would replace such str

Answer 1

Use the following:

> re.sub(r'(.+?)\1+', r'\1', 'xyzzyxxyzzyxxyzzyx')
'xyzzyx'
> re.sub(r'(.+?)\1+', r'\1', 'abcbaccbaabcbaccbaabcbaccba')
'abcbaccba'
> re.sub(r'(.+?)\1+', r'\1', 'iiiiiiiiiiiiiiiiii')
'i'

It basically matches a pattern that repeats itself (.+?)\1+, and removes everything but the repeating pattern, which is captured in the first group \1. Also note that using a reluctant qualifier here, i.e., +? will make the regex backtrack quite a lot.

DEMO.