PHP: Array Operators
Description
This is a Comprehensive PHP array operators tutorial from w3resource.com
List of array operators
| Name | Example | Result |
|---|---|---|
| Union | $x + $y | Union of $x and $y. The + operator appends elements of remaining keys from the right-sided array to the left-handed, but duplicated keys are not overwritten. |
| Equality | $x == $y | TRUE if $x and $y have the same key/value pairs. |
| Identity | $x === $y | TRUE if $x and $y have the same key/value pairs in the same order and of the same types. |
| Inequality | $x != $y | TRUE if $x is not equal to $y. |
| Inequality | $x <> $y | TRUE if $x is not equal to $y. |
| Non-identity | $x !== $y | TRUE if $x is not identical to $y. |
Example : array union (+) operator
In the following example, the union operator adds the last element from the $b array ($c = $a + $b) with $a array as "c=>" key is not present in $a array. In the second statement ($c = $b + $a) no element is added from $b as all the keys of $a array are present in $b array.
<?php
$a = array("a" => "apple", "b" => "banana");
$b = array("a" => "pear", "b" => "strawberry", "c" => "cherry");
$c = $a + $b; // Union of $a and $b
echo "Union of \$a and \$b : <br />";
var_dump($c);
$c = $b + $a; // Union of $b and $a
echo "<br />Union of \$b and \$a : <br />";
var_dump($c);
?>
Output:
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" }
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Example : array equality (==) and identity(===) operators
In the following example equality operator returns true as the two arrays have same key/value pairs whereas identity operator returns false as the key/value of the comparing arrays are same but not in same order.
<?php
$a = array("1" => "apple", "0" => "banana");
$b = array( "banana", "apple");
var_dump($a == $b);
var_dump($a === $b);
?>
Output:
bool(true) bool(false)
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