Let's take this array as an example:
$arr = array(
'foo' => 'foo',
'bar' => array(
'baz' => 'baz',
'candy' => 'candy',
'vegetable' => array(
'carrot' => 'carrot',
)
),
'vegetable' => array(
'carrot' => 'carrot2',
),
'fruits' => 'fruits',
);
Now how to do a general search to check if a value exists whether as a key or a value in the array and his sub-arrays.