Spread Operator (...)

The PHP Spread Operator (...) is a powerful feature introduced in PHP 5.6 that allows you to "unpack" or "spread" elements from arrays and traversable objects. It's also known as the splat operator or unpacking operator.

The spread operator is particularly useful in modern PHP development for creating more expressive and efficient code when working with arrays and variable function arguments.

Key Benefits of the PHP Spread Operator

1. Cleaner syntax for array merging and function calls

2. Better performance in some cases compared to array_merge()

3. More readable code when dealing with multiple arrays

4. Flexible for both array operations and function arguments
   
   
   

Here are a few common use cases for the operator:

Unpack and Merge Multiple Arrays

Here are a couple of examples for unpacking and merging arrays.  

 $array1 = [1, 2, 3];

 $array2 = [4, 5, 6];

 $array3 = [7, 8, 9];

 $merged = [...$array1, ...$array2, ...$array3];

 // Array (

 //  [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5

 //  [5] => 6 [6] => 7 [7] => 8 [8] => 9

 // )

 $original = ['b', 'c', 'd'];

 $newArray = ['a', ...$original, 'e'];

 // Array (

 //   [0] => a [1] => b [2] => c [3] => d [4] => e

 // )

Function Arguments

 // FUNCTION ARGUMENTS

 function addNumbers($a, $b, $c) {

    return $a + $b + $c;

 }

 $numbers = [2, 4, 6];

 $result = addNumbers(...$numbers);

 echo $result; // Output: 12

 function sum(...$numbers) {

    return array_sum($numbers);

 }

 $values = [1, 2, 3, 4, 5];

 echo sum(...$values); // Output: 15

Combining With Regular Elements

 // Combining with Regular Elements

 $first = [1, 2];

 $last = [5, 6];

 $combined = [...$first, 3, 4, ...$last];

 print_r($combined);

 // Output: Array ([0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6)

Usage With Associative Arrays

Notice that array keys are also considered making it perfect for merging associative arrays as well.  

 //With Associative Arrays

 $config1 = ['host' => 'localhost', 'port' => 3306];

 $config2 = ['username' => 'root', 'password' => 'secret'];

 $finalConfig = [...$config1, ...$config2];

 print_r($finalConfig);

// Output: Array ([host] => localhost [port] => 3306 [username] => root [password] => secret)

String To Array Conversion

 // String To Array Conversion

 $string = "hello";

 $chars = [...$string];

 print_r($chars);

 // Output: Array ([0] => h [1] => e [2] => l [3] => l [4] => o)

Practical Example of Merging 2 Configuration Arrays

Remember that when merging 2 associative arrays using the spread operator and brackets syntax, the second array in the will overwrite values with matching keys.  Take a look at the ‘debug’ key below:

 // Configuration Merging

 $defaultConfig = [

    'debug' => false,

    'cache' => true,

    'timeout' => 30

 ];

 $userConfig = [

    'debug' => true,

    'database' => 'mysql'

 ];

 $finalConfig = [...$defaultConfig, ...$userConfig];

 print_r($finalConfig);

 // Output: Array ([debug] => true [cache] => true [timeout] => 30 [database] => mysql)