In PHP, array is an extremely common data type. In practical applications, we often need to perform some operations on arrays, such as searching, sorting, filtering, etc. Among them, taking intersection is a relatively common operation. The array_intersect_key() function provided in PHP can be used to intersect two or more arrays (key comparison), that is, return the keys and values that exist in all given arrays.
array_intersect_key() function is used as follows:
array array_intersect_key( array $array1 , array $array2 [, array $... ] )
This function accepts two or more array parameters. It returns a new array containing a number of key-value pairs present in all arrays, indexed by the keys of the first argument array. Each parameter array can contain any number of key-value pairs, which are used to determine intersection.
Let’s look at a simple example:
$array1 = array('a' => 'apple', 'b' => 'banana', 'c' => 'coconut'); $array2 = array('b' => 'banana', 'c' => 'coconut', 'd' => 'date'); $result = array_intersect_key($array1, $array2); print_r($result);
The output result of the above code is:
Array ( [b] => banana [c] => coconut )
As you can see, only the key b is retained in the $result array and elements of c. This is because these two elements appear in both $array1 and $array2.
The following are some notes on this function:
The above is an introduction to the array_intersect_key() function in PHP. Using this function you can easily get the intersection from multiple arrays without the need for complex comparison operations. I hope this article can help you use arrays in PHP more effectively.
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