Online PHP editor | output for TsFlc

<?php // assuming only 2 characters find and replace $string = "Hello world."; $aa = str_split($string); //converts string into array $rp1 = 'aa'; //replace string 1 $rp2 = 'bb'; //replace string 2 $f1 = 'lo'; //find string 1 $f2 = 'ld'; // find string 2 function replaceChar($k1, $k2, $findStr, $replaceStr, $arr){ $str = $arr[$k1].$arr[$k2]; if($str == $findStr){ $ra = str_split($replaceStr); $arr[$k1] = $ra[0]; $arr[$k2] = $ra[1]; } return $arr; } for($i=0; $i < count($aa)-1; $i++){ $k1 = $i; $k2 = $i+1; $aa = replaceChar($k1, $k2, $f1, $rp1, $aa); //for replace first match string $aa = replaceChar($k1, $k2, $f2, $rp2, $aa); // for replace second match string } echo implode('', $aa);