How to check if an array contains a specific key in php

Question

I know how to check a value in an array, but how to check a value in an Iterator of an array?

$array = new ArrayIterator(array( '1QmRjtsw2UQ' => array('pubdate' => '26 Jun 15', 'alt' => '8 Year Old Beautifully Covers Thinking Out Loud', 'anchor text' => '8-yo \'Thinking Out Loud\''), 'eKqLaYrcf3A' => array('pubdate' => '25 Jun 15', 'alt' => 'Plane Lands On Truck', 'anchor text' => 'Plane Lands On Truck'), )); 

I am trying to check values ​​like 1QmRjtsw2UQ .

This does not work:

 if(in_array('1QmRjtsw2UQ', $array)); 

Answer 1

why don't you use array_key_exists ?

 if(array_key_exists('1QmRjtsw2UQ', $array)) { // do something } 

Answer 2

Try it,

 $array->offsetExists('1QmRjtsw2UQ');