Question

When checking a superglobal like $_GET or $_POST for existence of a value for a particular key, is there a method that encompasses the following functionality in a more concise way?

if (isset($_POST['foo']) && $_POST['foo'] !== '') {
    // ...
}

The isset() function by itself returns TRUE even when the value is an empty string '', so I can’t use that.

Using just $_POST['foo'] !== '' will work correctly by itself, but it emits an E_NOTICE for undefined index, which is undesirable.

The empty() function returns TRUE for the value "0", which is a valid value, so I can’t use that, either.

Am I missing something obvious, or is this really the best/only way to do it?

Answer 1

Probably you are looking for array_key_exists():

if (array_key_exists('foo', $_POST)){
    // will execute when $_POST['foo'] is set, even if to null, false, '' etc.
};

If you do not want to match empty string (''), then your solution is probably enough. Solution above gives you false only when the key does not exist.