Prepare array with false-Values for undefinded keys with array_fill_keys (in PHP >= 5.3.0)

Avoid hundrets isset() calls.php

<?php
$in_array=array("foo"=>"fooval","baz"=>"bazval");
$in_array+=array_fill_keys(array("foo","bar","baz"),false);
// array_fill_keys is since PHP 5.2.0

// useage:

echo $in_array["foo"]?:"foodef";
// short ternary operator is since PHP 5.3.0
echo "\n";
echo $in_array["bar"]?:"bardef";
//now you don't have to write:
// echo isset($in_array["bar"])?$in_array["bar"]):"bardef";
echo "\n";
echo $in_array["baz"]?:"bazdef";
echo "\n";

/* Output:
fooval
bardef
bazval
*/