substr
<?php
 $str = "Fast String Manipulation";
 echo substr($str,0,4) . substr($str,-9);
?>
Output
Fastipulation
explode
<?php
 $a = explode(":", "This:string:has:delimiters.");
 foreach ($a as $value) {
     echo ($value == "has" ? "had" : $value) . " ";
 }
?>
Output
This string had delimiters.