Arrays

    For a list of all array functions, see the array functions chapter in the documentation.

    An array in PHP is actually an ordered map. A map is a type that associates values to keys. This type is optimized for several different uses; it can be treated as an array, list (vector), hash table (an implementation of a map), dictionary, collection, stack, queue, and probably more. As array values can be other arrays, trees and multidimensional arrays are also possible.

    Explanation of those data structures is beyond the scope of this manual, but at least one example is provided for each of them. For more information, look towards the considerable literature that exists about this broad topic.

    Syntax

    Specifying with array()

    An array can be created using the array() language construct. It takes any number of comma-separated key => value pairs as arguments. 

    array(
    key  => value,
    key2 => value2,
    key3 => value3,
    ...
)

    The comma after the last array element is optional and can be omitted. This is usually done for single-line arrays, i.e. array(1, 2) is preferred over array(1, 2, ). For multi-line arrays on the other hand the trailing comma is commonly used, as it allows easier addition of new elements at the end.

    Note:

    A short array syntax exists which replaces array() with [].

    Example #1 A simple array

    <?php
$array1 = array(
    "foo" => "bar",
    "bar" => "foo",
);

// Using the short array syntax
$array2 = [
    "foo" => "bar",
    "bar" => "foo",
];

var_dump($array1, $array2);
?>

    The key can either be an int or a