Get first key in a (possibly) associative array?

What's the best way to determine the first key in a possibly associative array? My first thought it to just foreach the array and then immediately breaking it, like this:
foreach ($an_array as $key => $val) break;
Thus having $key contain the first key, but this seems inefficient. Does anyone have a better solution?

Answer :

You can use reset and key:
reset($array);
$first_key = key($array);
It's essentially the same as your initial code, but with a little less overhead, and it's more obvious what is happening.
Just remember to call reset, or you may get any of the keys in the array. You can also use endinstead of reset to get the last key.
If you wanted the key to get the first value, reset actually returns it:
$first_value = reset($array);
There is one special case to watch out for though (so check the length of the array first):
$arr1 = array(false);
$arr2 = array();
var_dump(reset($arr1) === reset($arr2)); // bool(true)



http://stackoverflow.com/questions/1028668/get-first-key-in-a-possibly-associative-array

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