Top 10 Laravel Collection Methods You May Have Never Used

Laravel Collections are an integral part of the framework, offering a fluent, convenient wrapper for working with arrays of data. While many developers are familiar with the basics, Laravel Collections offers many lesser-known methods that can significantly streamline your code and enhance productivity. Here are the top 10 Laravel Collection methods you may have never used:

1. `pluck`

The `pluck` method retrieves all of the values for a given key from an array or collection of arrays.

Example:

$users = collect([
    ['name' => 'John', 'email' => 'john@example.com'],
    ['name' => 'Jane', 'email' => 'jane@example.com'],
]);

$emails = $users->pluck('email');

// ['john@example.com', 'jane@example.com']

2. `partition`

The `partition` method may be used to separate elements that pass a given truth test from those that do not.

Example:

$collection = collect([1, 2, 3, 4, 5, 6]);

list($even, $odd) = $collection->partition(function ($i) {
    return $i % 2 === 0;
});

// $even: [2, 4, 6]
// $odd: [1, 3, 5]

3. `mapWithKeys`

The `mapWithKeys` method iterates through the collection and passes each value to the given callback. The callback should return an associative array with a single key/value pair.

Example:

$collection = collect([
    ['name' => 'John', 'email' => 'john@example.com'],
    ['name' => 'Jane', 'email' => 'jane@example.com'],
]);

$keyed = $collection->mapWithKeys(function ($item) {
    return [$item['email'] => $item['name']];
});

// ['john@example.com' => 'John', 'jane@example.com' => 'Jane']

4. `eachSpread`

The `eachSpread` method iterates over the collection's items and passes each nested array item into a callback as individual arguments.

Example:

$collection = collect([
    [1, 'John'],
    [2, 'Jane'],
]);

$collection->eachSpread(function ($id, $name) {
    echo "$id: $name";
});

// 1: John
// 2: Jane

5. `reject`

The `reject` method filters the collection using the given callback, removing the elements that pass the given truth test.

Example:

$collection = collect([1, 2, 3, 4]);

$filtered = $collection->reject(function ($value) {
    return $value > 2;
});

// [1, 2]

6. `tap`

The `tap` method passes the collection to the given callback and then returns the collection.

Example:

$collection = collect([2, 4, 3, 1, 5]);

$collection->tap(function ($col) {
    // Log the collection, or perform other actions
    Log::info($col);
})->sort();

// [1, 2, 3, 4, 5]

7. `crossJoin`

The `crossJoin` method cross joins the collection with the given arrays, returning a Cartesian product.

Example:

$collection = collect([1, 2]);

$matrix = $collection->crossJoin(['A', 'B']);

// [[1, 'A'], [1, 'B'], [2, 'A'], [2, 'B']]

8. `pipe`

The `pipe` method passes the collection to the given callback and returns the result.

Example:

$collection = collect([1, 2, 3]);

$piped = $collection->pipe(function ($col) {
    return $col->sum();
});

// 6

9. `flatMap`

The `flatMap` method iterates through the collection and passes each value to the given callback. The callback should return an array of key/value pairs, which will be flattened into a single array.

Example:

$collection = collect([
    ['name' => 'John', 'hobbies' => ['Reading', 'Swimming']],
    ['name' => 'Jane', 'hobbies' => ['Cycling']],
]);

$hobbies = $collection->flatMap(function ($item) {
    return $item['hobbies'];
});

// ['Reading', 'Swimming', 'Cycling']

10. `whenEmpty` and `whenNotEmpty`

The `whenEmpty` method executes the given callback when the collection is empty, while `whenNotEmpty` does the opposite.

Example:

$collection = collect([]);

$collection->whenEmpty(function ($col) {
    return $col->push('Default Value');
});

// ['Default Value']

$collection = collect([1, 2, 3]);

$collection->whenNotEmpty(function ($col) {
    return $col->push(4);
});

// [1, 2, 3, 4]

Laravel Collections offer an impressive array of methods beyond the basics. By exploring and utilizing these lesser-known methods like `pluck`, `partition`, `mapWithKeys`, `eachSpread`, `reject`, `tap`, `crossJoin`, `pipe`, `flatMap`, and the `whenEmpty/whenNotEmpty` pair, you can write more concise, readable, and efficient code. Dive into the Laravel documentation and experiment with these methods to unlock their full potential.