php man page for array_intersect_assoc

ARRAY_INTERSECT_ASSOC(3)						 1						  ARRAY_INTERSECT_ASSOC(3)

array_intersect_assoc - Computes the intersection of arrays with additional index check

SYNOPSIS
       array array_intersect_assoc (array  $array1, array  $array2, [array  $...])

DESCRIPTION
       array_intersect_assoc(3)  returns  an  array containing all the values of $array1 that are present in all the arguments. Note that the keys
       are used in the comparison unlike in array_intersect(3).

PARAMETERS
	      o $array1
		- The array with master values to check.

	      o $array2
		- An array to compare values against.

	      o $...
		- A variable list of arrays to compare.

RETURN VALUES
	Returns an associative array containing all the values in $array1 that are present in all of the arguments.

EXAMPLES
       Example #1

	      array_intersect_assoc(3) example

	      <?php
	      $array1 = array("a" => "green", "b" => "brown", "c" => "blue", "red");
	      $array2 = array("a" => "green", "b" => "yellow", "blue", "red");
	      $result_array = array_intersect_assoc($array1, $array2);
	      print_r($result_array);
	      ?>

	      The above example will output:

	      Array
	      (
		  [a] => green
	      )

	In our example you see that only the pair "a" => "green" is present in both arrays and thus is returned. The value "red" is  not  returned
       because in $array1 its key is 0 while the key of "red" in $array2 is 1, and the key "b" is not returned because its values are different in
       each array.

	The two values from the key => value pairs are considered equal only if (string) $elem1 === (string) $elem2 . In other words a strict type
       check is executed so the string representation must be the same.

SEE ALSO 
array_intersect(3), array_uintersect_assoc(3), array_intersect_uassoc(3), array_uintersect_uassoc(3), array_diff(3), array_diff_assoc(3).

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