php find a string in a string and select 4 charcsters after the string' code example

Example 1: get the string after a character in php

$data = "123_String";    
$whatIWant = substr($data, strpos($data, "_") + 1);    
echo $whatIWant;

Example 2: only display part of string php

substr('abcdef', 1);     // bcdef
substr('abcdef', 1, 3);  // bcd
substr('abcdef', 0, 8);  // abcdef
substr('abcdef', -1, 1); // f