I've heard that you get an error if you try to access a key in a hash that doesn't exist.

However, I seem to just get an empty string, or a null value.

Example:

```
<?php

$hash = array("abc" => 123,
              "def" => 456
);

echo "a key that's in the hash: <" . $hash["abc"] . "><br />";

echo "a key that's not in the hash: <" . $hash["ghi"] . ">";

?>

```

The output is:

```
a key that's in the hash: <123>
a key that's not in the hash: <>

```

**What's going on here?**

I'm using PHP v5.3.8.