regex for repeating words in a string in Python

Question

I have a good regexp for replacing repeating characters in a string. But now I also need to replace repeating words, three or more word will be replaced by two words.

Like

bye! bye! bye!

should become

bye! bye!

My code so far:

def replaceThreeOrMoreCharachetrsWithTwoCharacters(string): 
     # pattern to look for three or more repetitions of any character, including newlines. 
     pattern = re.compile(r"(.)\1{2,}", re.DOTALL) 
     return pattern.sub(r"\1\1", string)

Answer 1

假设您的需求中所谓的“单词”是由空格或字符串限制包围的一个或多个非空格字符，您可以尝试以下模式：

re.sub(r'(?<!\S)((\S+)(?:\s+\2))(?:\s+\2)+(?!\S)', r'\1', s)

Answer 2

You could try the below regex also,

(?<= |^)(\S+)(?: \1){2,}(?= |$)

Sample code,

>>> import regex
>>> s = "hi hi hi hi some words words words which'll repeat repeat repeat repeat repeat"
>>> m = regex.sub(r'(?<= |^)(\S+)(?: \1){2,}(?= |$)', r'\1 \1', s)
>>> m
"hi hi some words words which'll repeat repeat"

DEMO

Answer 3

I know you were after a regular expression but you could use a simple loop to achieve the same thing:

def max_repeats(s, max=2):
  last = ''
  out = []
  for word in s.split():
    same = 0 if word != last else same + 1
    if same < max: out.append(word)
    last = word
  return ' '.join(out)

As a bonus, I have allowed a different maximum number of repeats to be specified (the default is 2). If there is more than one space between each word, it will be lost. It's up to you whether you consider that to be a bug or a feature :)

Answer 4

Try the following:

import re
s = your string
s = re.sub( r'(\S+) (?:\1 ?){2,}', r'\1 \1', s )

You can see a sample code here: http://codepad.org/YyS9JCLO

Answer 5

def replaceThreeOrMoreWordsWithTwoWords(string):
    # Pattern to look for three or more repetitions of any words.
    pattern = re.compile(r"(?<!\S)((\S+)(?:\s+\2))(?:\s+\2)+(?!\S)", re.DOTALL)
    return pattern.sub(r"\1", string)