php - array_filter based on keys from another array -

i have 2 arrays:

$arr1 = array('a' => 10, 'b' => 20);

$arr2 = array('a' => 10, 'b' => 20, 'c' => 30);

how can use array_filter drop elements $arr2 don't exist in $arr1 ? "c" in example...

there function made purpose: array_intersect():

array_intersect — computes intersection of arrays

$arr2 = array_intersect($arr1, $arr2); 

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if want compare keys, not values array_intersect(), use array_intersect_key():

array_intersect_key — computes intersection of arrays using keys comparison

$arr2 = array_intersect_key($arr1, $arr2);  

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if want compare key=>value pairs, use array_intersect_assoc():

array_intersect_assoc — computes intersection of arrays additional index check

$arr2 = array_intersect_assoc($arr1, $arr2);