PHP Multidimensional Arrays: Arrays Inside Arrays

An array item can be another array. This lets you build tables and nested records.

A list of records

This is the most common shape: a list where each item is an associative array.

index.php

PHP

<?php
$products = [
    ["name" => "Notebook", "price" => 80, "stock" => 25],
    ["name" => "Pen", "price" => 12, "stock" => 100],
    ["name" => "Bag", "price" => 799, "stock" => 0],
];

echo $products[0]["name"] . "\n";
echo $products[2]["price"];

Output

OUTPUT

1
2

Notebook
799

Read it from left to right: $products[0] is the first product, and ["name"] is its name.

Loop through it

index.php

PHP

<?php
$products = [
    ["name" => "Notebook", "price" => 80],
    ["name" => "Pen", "price" => 12],
];

foreach ($products as $product) {
    echo $product["name"] . ": " . $product["price"] . "\n";
}

Output

OUTPUT

1
2

Notebook: 80
Pen: 12

A grid (rows and columns)

index.php

PHP

<?php
$grid = [
    [1, 2, 3],
    [4, 5, 6],
];

echo $grid[1][2] . "\n";   // row 1, column 2

foreach ($grid as $row) {
    echo implode(" ", $row) . "\n";
}

Output

OUTPUT

1
2
3

6
1 2 3
4 5 6

Nested records

index.php

PHP

<?php
$order = [
    "id" => 1042,
    "customer" => ["name" => "Ravi", "city" => "Surat"],
    "items" => [
        ["sku" => "A1", "qty" => 2],
        ["sku" => "B7", "qty" => 1],
    ],
];

echo $order["customer"]["city"] . "\n";
echo count($order["items"]) . " items\n";
echo $order["items"][1]["sku"];

Output

OUTPUT

1
2
3

Surat
2 items
B7

Change a nested value

index.php

PHP

<?php
$order = ["customer" => ["city" => "Surat"]];

$order["customer"]["city"] = "Pune";
$order["customer"]["phone"] = "99999";

print_r($order);

Output

OUTPUT

Array
(
    [customer] => Array
        (
            [city] => Pune
            [phone] => 99999
        )

)

Safe reading with ??

When a nested key might not exist, chain ??.

index.php

PHP

<?php
$order = ["customer" => ["name" => "Ravi"]];

echo $order["customer"]["email"] ?? "no email";

Output

OUTPUT

no email

Pull one column out

index.php

PHP

<?php
$products = [
    ["name" => "Notebook", "price" => 80],
    ["name" => "Pen", "price" => 12],
];

print_r(array_column($products, "price", "name"));

Output

OUTPUT

Array
(
    [Notebook] => 80
    [Pen] => 12
)

array_column() takes one field from every row. The optional third argument sets the keys.

info

This is how data really looks

Database results, JSON from an API and your own shopping cart all arrive as arrays of arrays. Getting comfortable with this shape pays off in every later chapter.