PHP Interview Questions

What are the differences between echo and print in PHP?

• Both statements print and echo are used to output/print data on the screen.
• The echo statement does not return any value whereas print always returns an integer value (1).
• The echo accepts multiple arguments whereas print only accepts a single argument.
• Both echo and print statements can be used with or without parentheses ().

During development, the developer needs to go through loops to prepare a single dimensional array out of a multi-dimensional array.

Laravel provides many helpers which come handy in multiple ways and saves developers work.

One of such is Arr::flatten() which flattens a multi-dimensional array into a single level by default.

Tested with Laravel versions 5.8, 6 and 7.

We need to import Illuminate\Support\Arr namespace with use keyword.

Kindly check for your version on the official DOC for Laravel Helper Arr::flatten(). This link will take you to Laravel 7 Documentation.

Syntax

Arr::flatten(array $array, [int $depth = INF])

Parameters

$array (necessary)

• The first parameter is necessary and must be an array that needs to be flattened.
• Laravel will extract elements and provides us with a new single dimension array based on the depth parameter.

$depth (optional)

• The second parameter specifies the depth and it’s an optional parameter.
• This value must be an integer type.
• The depth specifies how deep a nested array should be flattened.
• The default value for depth is infinity(INF) from which Laravel will extract elements and provides us with a new single dimension array.

Return value

It returns a new 1-D flattened array.

Example

$data = [
    'country' => 'India 🇮🇳',
    'languages' => [
        'Gujarati',
        'Hindi',
        'Sanskrit',
        'Tamil',
        'Urdu',
    ],
];

dd(
	Arr::flatten($data)
);

Output

array:3 [
  0 => "India 🇮🇳"
  1 => "Gujarati"
  2 => "Hindi"
  3 => "Sanskrit"
  4 => "Tamil"
  5 => "Urdu"
]

Deeper Nested Arrays

This method also works on our specified level deep. We simply need to pass the appropriate depth parameter in order to flatten deeper multi-dimensional or nested arrays.

Example with 2 levels deep

$data = [[12, [2, 4], 124, 7, 10, 8, [15, [6, 7]]]];

dd(
    Arr::flatten($data, 2)
);

Output for 2 levels deep

array:9 [
  0 => 12
  1 => 2
  2 => 4
  3 => 124
  4 => 7
  5 => 10
  6 => 8
  7 => 15
  8 => array:2 [
    0 => 6
    1 => 7
  ]
]

Example with INF level deep

$data = [[12, [2, 4], 124, 7, 10, 8, [15, [6, 7]]]];

dd(
    Arr::flatten($data, INF)
);

Output for INF level deep

array:10 [
  0 => 12
  1 => 2
  2 => 4
  3 => 124
  4 => 7
  5 => 10
  6 => 8
  7 => 15
  8 => 6
  9 => 7
]

Resources

• Laravel Arr flatten method documentation
• Laravel Arr flatten helper method

Happy 😄 coding

With ❤️ from 🇮🇳

Related Articles

Deepen your understanding with these curated continuations.

View All Articles

Laravel 5 min read

Unsigned Columns in Laravel Migrations

How to declare unsigned integer columns in Laravel migrations using unsignedBigInteger(), foreignId(), and the unsigned() modifier. Updated for Laravel 12.

Vishnu Dec 30, 2025

Laravel 5 min read

Nested Eager Loading in Laravel Eloquent Explained

Reduce database queries in Laravel using nested eager loading. Learn the syntax, conditional loading, and how to optimize deeply related Eloquent models.

Vishnu Nov 02, 2024

Laravel 5 min read

Check Your Laravel Version from the Command Line

How to check your Laravel version using php artisan --version, php artisan about, composer show, and app()->version(). Updated for Laravel 12 in 2026.

Vishnu Nov 01, 2024