## Array Operators

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);
?>
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"
}

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(=> "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.