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PHP Array Creation and Initialization Guide

M66 2025-07-01

How to Create and Initialize a PHP Array

PHP arrays are essential data structures for storing and organizing data. In PHP programming, creating and initializing arrays is a common operation. This article will guide you on how to create and initialize a PHP array, providing code examples to help you understand the process better.

Creating an Empty Array

In PHP, you can create an empty array using array() or []. Here are code examples of both methods:

// Using array() to create an empty array
$array1 = array();

// Using [] to create an empty array
$array2 = [];

Creating an Array with Default Values

Besides creating an empty array, you can also create an array with default values using the array_fill() function. This will initialize each element with the same value. Below is an example:

// Create an array with 5 elements, each initialized to 0
$array = array_fill(0, 5, 0);

// Print the array
print_r($array);

The output will be:

Array
(
    [0] => 0
    [1] => 0
    [2] => 0
    [3] => 0
    [4] => 0
)

Initializing an Array with Known Elements

If you already know the elements you want to store in the array, you can initialize the array directly. Below is an example using either array() or [] syntax:

// Initialize an array with multiple elements
$array = array('apple', 'banana', 'orange');

// Print the array
print_r($array);

The output will be:

Array
(
    [0] => apple
    [1] => banana
    [2] => orange
)

Creating an Associative Array

Associative arrays use string keys to access values. You can create an associative array using array() or [], separating key-value pairs with the => symbol. Below is an example:

// Create an associative array
$array = array(
    'name' => 'John Doe',
    'age' => 30,
    'email' => 'john@example.com'
);

// Print the array
print_r($array);

The output will be:

Array
(
    [name] => John Doe
    [age] => 30
    [email] => john@example.com
)

Adding Elements to an Array Dynamically

In addition to initializing elements during array creation, you can also dynamically add elements to an existing array. You can do this using the array_push() function or directly through assignment. Here are two examples:

// Use array_push() to add elements
$array = array('apple', 'banana');
array_push($array, 'orange');

// Use assignment to add elements
$array[] = 'grape';

// Print the array
print_r($array);

The output will be:

Array
(
    [0] => apple
    [1] => banana
    [2] => orange
    [3] => grape
)

Conclusion

Creating and initializing arrays in PHP is one of the basic operations when writing programs. By using array() or [], you can easily create empty arrays, arrays with default values, arrays with predefined elements, and associative arrays. Additionally, you can dynamically add elements to an existing array using array_push() or direct assignment. We hope the code examples in this article will help you better understand how to work with PHP arrays.

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