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javaregexreplacerepeatletters

How to remove 3 or more consecutive letters in java into 2 consecutive letters?

I'm trying to process strings with repeated chars in order to find the correct word in a dictionary.

The approach I must use is to find words with 3 or more consecutive letters and remove them into 2 consecutive letters.

Then I'll look for in the dictionary if this word exists. If the word doesn't exist, then I must remove the two consecutive letters into 1 letter only.

Example: 

gooooooood -> good (this existis)
awesooooome -> awesoome (this doesn't exist) -> awesome (this exists)
aaawwwesooooooommmme -> aawwesoomme (this doesn't exist) -> awesome (this exists)

I'm working with JAVA and i'm already using this regular expression to get the words with 3 or more repeated letters in a string:

Pattern p = Pattern.compile("\\b\\w*(\\w)\\1{2}\\w*");
Solution

  • You can use this regex ("pure version"):

    (\b\w*?)(\w)\2{2,}(\w*)

    String version:

    "(\\b\\w*?)(\\w)\\2{2,}(\\w*)"

    You should use replaceAll(regex, "$1$2$2$3")

    Explanation

    (\b\w*?) // capture group 1 is lazy
(\w)     // capture group 2 captures the first occurrence of the char
\2{2,}   // char may occur 2 or more times...
(\w*)    // capture group 3

    Note that the $number in the replacement refers to the contents of the corresponding capture group.