PHP Array Operators

PHP provides special operators for working with arrays. These operators let you combine arrays and compare them in different ways. Understanding the difference between union and merge is crucial!

Array Operators Overview

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Array Union (+)

Combines arrays, keeping the FIRST value for duplicate keys:

<?php
$arr1 = ["a" => "apple", "b" => "banana"];
$arr2 = ["b" => "blueberry", "c" => "cherry"];

$result = $arr1 + $arr2;
print_r($result);
// ["a" => "apple", "b" => "banana", "c" => "cherry"]
// Note: "banana" kept, not "blueberry"
?>

Array Equality (==)

Checks if arrays have same key-value pairs (order doesn't matter):

<?php
$a = ["x" => 1, "y" => 2];
$b = ["y" => 2, "x" => 1];  // Different order

var_dump($a == $b);  // true (same pairs, order ignored)
?>

Array Identity (===)

Checks if arrays have same key-value pairs in same order with same types:

<?php
$a = ["x" => 1, "y" => 2];
$b = ["y" => 2, "x" => 1];  // Different order

var_dump($a === $b);  // false (different order)

$c = ["x" => 1, "y" => 2];
var_dump($a === $c);  // true (same order, same types)
?>

Summary

What's Next?

Congratulations! You've completed Module 3 and mastered all PHP operators. In the next module, we'll dive into Control Flow - using if statements, loops, and switch statements to control program execution!