a17.php

<?php
$students = [
    "john" => [
        "age" => 25,
        "class" => 12,
        "roll" => 5
    ],
    "doe" => [
        "age" => 26,
        "class" => 11,
        "roll" => 6
    ],
    "smith" => [
        "age" => 27,
        "class" => 10,
        "roll" => 7
    ],
    "alex" => [
        "age" => 28,
        "class" => 9,
        "roll" => 8
    ]
];

$multidimensionalFruitsArray = [
    "berries" => [
        "strawberry",
        "blueberry",
        "blackberry"
    ],
    "citrus" => [
        "orange",
        "lemon",
        "lime"
    ],
    "tropical" => [
        "banana",
        "mango",
        "pineapple"
    ]
];

$multiDimensionlNumbers = [
    [1,2,3],
    [4,5,6],
    [7,8,9]
];

$invoice = [
    "invoiceNumber" => "INV-123",
    "invoiceDate" => "2021-01-01",
    "invoiceItems" => [
        [
            "item" => "item1",
            "quantity" => 2,
            "price" => 100
        ],
        [
            "item" => "item2",
            "quantity" => 3,
            "price" => 200
        ],
        [
            "item" => "item3",
            "quantity" => 4,
            "price" => 300
        ]
    ]
];