php man page for array_intersect_ukey

ARRAY_INTERSECT_UKEY(3) 						 1						   ARRAY_INTERSECT_UKEY(3)

array_intersect_ukey - Computes the intersection of arrays using a callback function on the keys for comparison

SYNOPSIS
       array array_intersect_ukey (array  $array1, array  $array2, [array  $...], callable  $key_compare_func)

DESCRIPTION
       array_intersect_ukey(3)	returns  an  array containing all the values of $array1 which have matching keys that are present in all the argu-
       ments.

PARAMETERS
	      o $array1
		- Initial array for comparison of the arrays.

	      o $array2
		- First array to compare keys against.

	      o $...
		- Variable list of array arguments to compare keys against.

	      o $key_compare_func
		- The comparison function must return an integer less than, equal to, or greater than zero if the first argument is considered	to
		be respectively less than, equal to, or greater than the second.
		int callback (mixed  $a, mixed	$b)

RETURN VALUES
	Returns the values of $array1 whose keys exist in all the arguments.

EXAMPLES
       Example #1

	      array_intersect_ukey(3) example

	      <?php
	      function key_compare_func($key1, $key2)
	      {
		  if ($key1 == $key2)
		      return 0;
		  else if ($key1 > $key2)
		      return 1;
		  else
		      return -1;
	      }

	      $array1 = array('blue'  => 1, 'red'  => 2, 'green'  => 3, 'purple' => 4);
	      $array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan'	 => 8);

	      var_dump(array_intersect_ukey($array1, $array2, 'key_compare_func'));
	      ?>

	      The above example will output:

	      array(2) {
		["blue"]=>
		int(1)
		["green"]=>
		int(3)
	      }

	In our example you see that only the keys 'blue' and 'green' are present in both arrays and thus returned. Also notice that the values for
       the keys 'blue' and 'green' differ between the two arrays. A match still occurs because only the keys are checked. The values returned  are
       those of $array1.

SEE ALSO
       array_diff(3),  array_udiff(3),	array_diff_assoc(3), array_diff_uassoc(3), array_udiff_assoc(3), array_udiff_uassoc(3), array_diff_key(3),
       array_diff_ukey(3), array_intersect(3), array_intersect_assoc(3), array_intersect_uassoc(3), array_intersect_key(3).

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