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Using a regular expression to replace upper case repeated letters in python with a single lowercase letter

Asked 2010-11-10T14:21:46.833
42

I am trying to replace any instances of uppercase letters that repeat themselves twice in a string with a single instance of that letter in a lower case. I am using the following regular expression and it is able to match the repeated upper case letters, but I am unsure as how to make the letter that is being replaced lower case.

import re
s = 'start TT end'
re.sub(r'([A-Z]){2}', r"\1", s)
>>> 'start T end'

How can I make the "\1" lower case? Should I not be using a regular expression to do this?

python regex capitalization
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2 Answers

0

You can do it with a regular expression, just pass a function as the replacement like the docs say. The problem is your pattern.

As it is, your pattern matches runs of any two capital letters. I'll leave the actual pattern to you, but it starts with AA|BB|CC|.

answered 2010-11-10T14:27:49.653
0

WARNING! This post has no re as requested. Continue with your own responsibility!

I do not know how possible are corner cases but this is how normal Python does my naive coding.

import string
s = 'start TT end AAA BBBBBBB'
for c in string.uppercase:
    s = s.replace(c+c,c.lower())
print s
""" Output:
start t end aA bbbB
"""
answered 2010-11-10T15:55:27.150

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