PHP：在数组中查找数组，不进行循环

Question

I have a simple array of boolean arrays as follows:

array(
    array('dog' => true),
    array('cat' => true),
    array('bird' =>false),
    array('fish' => true)
)

How can I find an entry, such as 'cat', without a loop construct? I think I should be able to accomplish this with a php array function, but the solution is eluding me! I just want to know if 'cat' is a valid key - I'm not interested in it's value.

In the example above, 'cat' should return true, while 'turtle' should return false.

Answer 1

$array = array(
  array('dog' => true),
  array('cat' => true),
  array('bird' =>false),
  array('fish' => true)
);

array_walk($array,'test_array');

function test_array($item2, $key){
$isarray =  is_array($item2) ? 'Is Array<br>' : 'No array<br>';
echo $isarray;
}

using array_walk example in the manual

Output:

Is Array
Is Array
Is Array
Is Array

Ideone