There would be no difference at all if you use the second one as a replacement of first one.
Why: This is due to behaviour of intval function.
intval Returns integer value of variable on success, or 0 on failure. Empty arrays return 0, non-empty arrays return 1.
Point to be noticed: 0 is considered as false, and any other non-zero integer value considered as true in PHP.
array_filter filters data based on return value of callable function which should be either true of false.
Now in your situation you're calling array_filter in two manners.
array_filter( array_map( 'intval', (array) $_POST['product_ids'] ) )
- In this you're passing an array of integers to
array_filter as array_map will loop over array and convert each value to corresponding integer by calling intval function. - Now as there is no parameter passed in
array_filter so by default empty function will be used and only numeric but not zero(0) values remains.
array_filter( (array) $_POST['product_ids'], 'intval' )
- In this you are calling
array_filter but intval as callable function, which will convert each value to corresponding integer. Main catch is here, if corresponding value is 0 then it will be false, otherwise true, which is equivalent to empty function in this case.
Note: This doesn't apply to other functions and would not create same results. See this by comparing intval and is_string function.
// Input data $entry = [ 0 => 'foo', 1 => false, 2 => -1, 3 => null, 4 => '', 5 => '0', 6 => 0, ]; // comparison for intval function print_r(array_filter( array_map( 'intval', $entry ) )); print_r(array_filter( $entry, 'intval' )); Output: Array ( [2] => -1 ) Array ( [2] => -1 ) // but if you try another function like is_string print_r(array_filter( array_map( 'is_string', $entry ) )); print_r(array_filter( $entry, 'is_string' )); Output: Array ( [0] => 1 [4] => 1 [5] => 1 ) Array ( [0] => foo [4] => [5] => 0 )
