Replace repeating characters with only one character in php

Question

I want to check if a string contains more than or equals 3 times a letter/number and replace it with only one letter/number. For example:

IIIII havvvvve a bigggg tesssssttttt tomorrow soooo iiii 2222551111 haveeee to do this rightttttt

To became like this

I have a big test tomorrow so i 2551 have to do this right. 

How can this be done with preg_replace ?

Answer 1

Regex:

([A-Za-z0-9])\1\1+

This would match more than or equals 3 times a letter/number and captures the first letter or Number. Finally the whole string was replaced with the character in the group index 1.

Replacement string:

\1

DEMO

<?php
$text = 'IIIII havvvvve a bigggg tesssssttttt tomorrow soooo iiii 2222551111 haveeee to do this rightttttt';
$pattern = '~([A-Za-z0-9])\1\1+~';
echo preg_replace($pattern,'\1',$text);
?>

Output:

I have a big test tomorrow so i 2551 have to do this right

Answer 2

([A-Za-z0-9])(\1{2,})?

Try this.Replace with $1.

See demo..

http://regex101.com/r/sA7pZ0/27