If you have a value and want to find the key, use array_search() like this: $arr = array (‘first’ => ‘a’, ‘second’ => ‘b’, ); $key = array_search (‘a’, $arr); $key will now contain the key for value ‘a’ (that is, ‘first’).
array_key_exists does NOT work recursive (as Matti Virkkunen already pointed out). Have a look at the PHP manual, there is the following piece of code you can use to perform a recursive search: <?php function array_key_exists_r($needle, $haystack) { $result = array_key_exists($needle, $haystack); if ($result) return $result; foreach ($haystack as $v) { if (is_array($v)) { $result … Read more
It is not considered as OK — even if it will work in most cases. Basically, when PHP sees this : echo $array[key]; It will search for a constant, defined with define, called key — and, if there is none, if will take the ‘key’ value. But, if there is something like this earlier in … Read more