Definition and usage
The array_intersect_key() function calculates the intersection of arrays using key name comparison.
array_intersect_key() returns an array containing the values of all key names that appear in the compared array and appear in all other parameter arrays.
Note: Only key names are used for comparison.
Grammar
array_intersect_key(array1,array2,array3...)
Parameters
Description
array1 required. The first array to compare with other arrays.
array2 required. The array to compare to the first array.
array3 is optional. The array to compare to the first array. There can be multiple.
Example 1
"Cat",1=>"Dog",2=>"Horse"); $a2=array(2=>"Bird", 0=>"Cat",4=>"Fish"); print_r(array_intersect_key($a1,$a2)); ?>
Output:
Array ( [0] => Cat [2] => Horse )
Example 2
"Cat",1=>"Dog",2=>"Horse"); $a2=array(2=>"Bird", 3=>"Rat",4=>"Fish"); $a3=array(2=>"Dog",6=>"Cow",7=>"Bird"); print_r(array_intersect_key ($a1,$a2,$a3)); ?>
Output:
Array ( [2] => Horse )