- substr: documentation ( source)
- strrpos: documentation ( source)
<?php
$str = "Hello, How are you ? this: is testing";
$chars = [",", "|", ":"];
$pos =0;
foreach($chars as $char){
if(strrpos($str, $char)>$pos) $pos = strrpos($str, $char);
}
if($pos == 0) $pos=strlen($str);
echo substr($str, 0, $pos);