array_walk always passing 0 as the parameter

array_walk is passing (int)0 as the parameter every time. What am I doing wrong?

I have a method to clean data, FilterInput::clean($value,$type), which I'm calling. I need to pass it the variable and the type I expect it to be.

When array_walk calls the function, I pass the variable type ('string' or 'int') to the method, but when it get's there the parameter always =0.

My code:

$data = array();
$data[0] = array('A Value','Another Value','Different Value');
$data[1] = array('12345','54321','11223');

array_walk( $data[0], array('FilterInput','clean'), 'string' );
array_walk( $data[1], array('FilterInput','clean'), 'int' );


Thanks!

Mike
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