<?php
$xyz = array ('a'=>'value1', 'b'=>'', 'c'=>'value3');
var_dump ($xyz); echo '<br />'; // let's see what we have
if (isset($xyz['b'])) $foo = $xyz['b']; // no complaints here
$foo = $xyz['b']; // this crashes
echo 'foo is set to:', $foo, ': end', '<br />';