3v4l.org

run code in 300+ PHP versions simultaneously
<?php $num = '7778855'; $mask = 'aabb'; $pattern = '/()?'; $arr = array(''); for($i=0;$i<strlen($mask);$i++) if(in_array($mask[$i] , $arr)) $pattern .= '\\'.array_search($mask[$i] , $arr); else {$pattern .= '([^\g{-1}])';$arr[] = $mask[$i];} $pattern .= '/'; var_dump($pattern); var_dump(preg_replace($pattern, '<$0>', $num));
Output for 4.3.11, 4.4.0 - 4.4.5, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.1, 5.3.19 - 5.3.29, 5.4.9 - 5.4.45, 5.5.24 - 5.5.35, 5.6.7 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
string(31) "/()?([^\g{-1}])\1([^\g{-1}])\2/" Warning: preg_replace(): Compilation failed: range out of order in character class at offset 10 in /in/frSgc on line 11 NULL
Output for 4.4.6 - 4.4.9, 5.2.2 - 5.2.17, 5.3.0 - 5.3.18, 5.4.0 - 5.4.8
string(31) "/()?([^\g{-1}])\1([^\g{-1}])\2/" string(9) "<777>8855"
Output for 4.3.0 - 4.3.10
string(31) "/()?([^\g{-1}])\1([^\g{-1}])\2/" Warning: Compilation failed: range out of order in character class at offset 10 in /in/frSgc on line 11 NULL
preferences:
273.48 ms | 402 KiB | 360 Q