The PHP `maybe` function

Posted by on June 17, 2013 · 2 mins read

Sometimes you just have a revelation, something that has bothered you for years that is actually quite easy to solve. For me, one of those things was the common PHP-scenario in which you check if a certain array key exists, if so return it, and otherwise return some default value. This is relatively easy with a ternary operator:

$var = array_key_exists($someHash, 'key') ? $someArray['key'] : 'default';

What bugs me about this though is the repetition: You have to type both $someHash and key twice. It’s a small thing, but it’s been bothering me for ages. Actually I think it started actively bothering me when I started using JavaScript on a daily basis, where you can simply use:

var v = someHash['key'] || 'default';

A similar construct in PHP would not only return the wrong value - it would also raise a Notice if the key wasn’t present. So last week I wrote this function:

 * Returns the key $k on array $arr if it exists,
 * the default otherwise.
 * @param array $arr The array to check
 * @param string $k The key to return
 * @param mixed $default The default value if the key doesn't exist.
 * @return string
function maybe($arr, $k, $default = '') {
	return array_key_exists($k, $arr) ? $arr[$k] : $default;

And now I can simply use:

$var = maybe($someHash, 'key', 'default');

Why I haven’t thought this before is beyond me. I’m very happy about it though.

EDIT: The only downside to this is of course performance - contrary to the ternary operator all possible results will be evalutated. When they’re simple types the difference is negligible though, and probably worth the increased simplicity. Be wary when using this for something more computationally intensive though.