- strpos: documentation ( source)
- var_export: documentation ( source)
- str_replace: documentation ( source)
<?php
$myarr = array("world cup");
foreach($myarr as &$v){
if(strpos($v,'o')!==false)
$myarr[] = str_replace('o','O',$v);
if(strpos($v,'O')!==false)
$myarr[] = str_replace('O','o',$v);
}
var_export($myarr);