replace text in string php

phpCopy<?php
$mystring = "This is my string.";
echo("This is the string before replacement: ");
echo($mystring);
echo("\n");
$mynewstring = str_replace(" my ", " ", $mystring);
echo("Now, this is the string after replacement: ");
echo($mynewstring);
?>

<?php
$string = str_ireplace("FoX", "CAT", "the quick brown fox jumps over the lazy dog");
echo $string; // the quick brown CAT jumps over the lazy dog
?>