Using PHP's array() Function to Create Indexed and Associative Arrays

Function Overview

The array() function is a built‑in PHP function used to create arrays. It accepts any number of arguments and can produce either an indexed array or an associative array based on the supplied values.

Creating Indexed Arrays

Indexed arrays are the default and most common array type in PHP. To create one, simply pass the values to array():

$names = array("John", "Jane", "David", "Alice");

In this example, $names is an indexed array containing four elements. Accessing elements uses zero‑based indexes, e.g., $names[0] yields "John" and $names[1] yields "Jane".

Creating Associative Arrays

Associative arrays use custom keys that map to values. Keys and values are separated by the => operator and passed to array():

$person = array("name" => "John", "age" => 25, "gender" => "male");

The resulting $person array contains three key‑value pairs. Values can be accessed via their keys, such as $person["name"] returning "John" and $person["age"] returning 25.

Important Considerations

Parameter count is unlimited; array() can receive any number of arguments separated by commas.

Parameter types are flexible: strings, integers, floats, or any variable type can be used.

Indexed array keys start at 0 and increment automatically; associative array keys can be strings or integers.

If both string and numeric keys are supplied, PHP converts numeric keys to integers automatically.

Example Code

Below are several practical examples illustrating how to use array() to create different kinds of arrays:

// Create an empty array
$emptyArray = array();

// Create an indexed array
$fruits = array("Apple", "Banana", "Orange");

// Create an associative array
$person = array("name" => "John", "age" => 25, "gender" => "male");

// Create a mixed array containing both indexed and associative elements
$mixedArray = array("Apple", "Banana", "color" => "Red", "size" => "Medium");

// Create a nested array
$nestedArray = array(array("Apple", "Banana"), array("Orange", "Grape"));

// Access elements in arrays
echo $fruits[1]; // outputs: Banana
echo $person["name"]; // outputs: John

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