## 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 \$becho "Union of \\$a and \\$b: \n";var_dump(\$c);\$c = \$b + \$a; // Union of \$b and \$aecho "Union of \\$b and \\$a: \n";var_dump(\$c);\$a += \$b; // Union of \$a += \$b is \$a and \$becho "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.