Hidden Methods Beginner Since Laravel 9.x

Arr::undot()

Expand a flat dot-notation array back into a fully nested structure — the inverse of Arr::dot().

Overview

Arr::dot() is well known for flattening nested arrays into dot notation. But its inverse, Arr::undot(), is far less known. It takes a flat array with dot-notation keys and reconstructs the nested structure.

Usage

use Illuminate\Support\Arr;

$flat = [
    'user.name' => 'Taylor',
    'user.email' => '[email protected]',
    'user.address.city' => 'Little Rock',
    'user.address.state' => 'AR',
];

Arr::undot($flat);
// [
//     'user' => [
//         'name' => 'Taylor',
//         'email' => '[email protected]',
//         'address' => [
//             'city' => 'Little Rock',
//             'state' => 'AR',
//         ],
//     ],
// ]

When to Use

  • Reconstructing config arrays from flat key-value stores (databases, Redis, .env overrides)
  • Transforming form input that uses dot notation back into nested data
  • Processing flattened API responses or CSV imports
Read the Laravel documentation

Tags

Collections Helpers