Best Way to Initialize an Empty Array in PHP

An array in PHP is used to store multiple values in a single variable. PHP array can hold similar or different types of data. There are three different types of array in PHP:

• Indexed Array
• Associative Array
• Multidimensional Array

There are different ways to initialize an empty array in PHP.

1. Using an Empty Array Declaration

The simplest and most efficient way to initialize an empty array in PHP is:

$array = [];
// or
$array = array();

Example: Basic example to create and initialize an array in PHP.

<?php

$arr1 = [10, 20, 30, 40, 50];
var_dump($arr1);

$arr2 = array(10, 20, 30, 40, 50);
var_dump($arr2);

?>

Why Choose [] Over array()?

• The [] syntax was introduced in PHP 5.4 and is more concise and readable.
• The array() function is still valid and necessary for versions of PHP older than 5.4.
• Performance-wise, [] and array() are virtually the same.

2. Using array_fill() to Predefine an Empty Array Structure

If you need an array with a fixed number of elements initialized to a default value, use array_fill():

// Creates an array with 5 null values
$array = array_fill(0, 5, null);

Example: Initializing an array using array_fill() function.

<?php

$arr = array_fill(0, 5, null);
var_dump($arr);

?>

3. Initializing a Multidimensional Empty Array

The basic method to initializing a Multidimensional array is by using [] or array() function.

arr = [num1, num2, arr1]

Example: Basic example to create a multidimensional array.

<?php

// Initializing multidimensional array using []
$arr1 = [10, 20, 30, [1, 2, 3], [4, 5, [6]]];
print_r($arr1);

// Initializing multidimensional array
// using array() function
$arr2 = array(10, 20, 30, array(1, 2, 3), array(4, 5, array(6)));
print_r($arr2);

?>

4. Initializing a Multidimensional Associative Array

The associative array is an array that contains data in key, value format.

$multiArray = [
    'users' => [],
    'posts' => []
];

Example: Creating a multidimensional associative array.

<?php 

$student1 = [
	"FirstName" => "Akash", 
	"LastName" => "Singh", 
	"Education" => [
	    "Batch" => "B. Tech", 
	    "RollNo" => "2121122"
	]
]; 

print_r($student1); 

$student2 = array(
	"FirstName" => "Raj", 
	"LastName" => "Kumar", 
	"Education" => array(
	    "Batch" => "MCA", 
	    "RollNo" => "234454433"
	)
); 

print_r($student2); 

?>