# Array Operators

Domains:
Array Operators
Example Name Result
$a +$b Union Union of $a and$b.
$a ==$b Equality TRUE if $a and$b have the same key/value pairs.
$a ===$b Identity TRUE if $a and$b have the same key/value pairs in the same order and of the same types.
$a !=$b Inequality TRUE if $a is not equal to$b.
$a <>$b Inequality TRUE if $a is not equal to$b.
$a !==$b Non-identity TRUE if $a is not identical to$b.

The + operator returns the right-hand array appended to the left-hand array; for keys that exist in both arrays, the elements from the left-hand array will be used, and the matching elements from the right-hand array will be ignored.

<?php
$a = array("a" => "apple", "b" => "banana");$b = array("a" => "pear", "b" => "strawberry", "c" => "cherry");

$c =$a + $b; // Union of$a and $b echo "Union of \$a and \$b: \n"; var_dump($c);

$c =$b + $a; // Union of$b and $a echo "Union of \$b and \$a: \n"; var_dump($c);

$a +=$b; // Union of $a +=$b is $a and$b
echo "Union of \$a += \$b: \n";
var_dump($a); ?> When executed, this script will print the following: Union of$a and $b: array(3) { ["a"]=> string(5) "apple" ["b"]=> string(6) "banana" ["c"]=> string(6) "cherry" } Union of$b and $a: array(3) { ["a"]=> string(4) "pear" ["b"]=> string(10) "strawberry" ["c"]=> string(6) "cherry" } Union of$a += $b: array(3) { ["a"]=> string(5) "apple" ["b"]=> string(6) "banana" ["c"]=> string(6) "cherry" }  Elements of arrays are equal for the comparison if they have the same key and value. Example #1 Comparing arrays <?php$a = array("apple", "banana");
$b = array(1 => "banana", "0" => "apple"); var_dump($a == $b); // bool(true) var_dump($a === \$b); // bool(false)
?>


See also the manual sections on the Array type and Array functions.

Page structure
Terms