Operators for working with PHP arrays

Here is a list of operators working with PHP arrays:

The + operator appends the right-hand array to the array located on the left NOT overwriting items with duplicate keys.

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

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

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

After its execution, the script displays 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"
}

When comparing, the elements of an array are considered identical if both the key and the corresponding value match.

<?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: Arrays and Array Functions.