Common Laravel Collection Methods and Their Usage

Laravel Eloquent returns a Collection object that provides many useful methods for filtering, modifying, and analyzing data. You can also create a collection directly from an array using the collect helper.

Key methods demonstrated include:

filter() : Returns a new collection containing items that satisfy a callback condition. Example:

$filter = $collection->filter(function($value, $key) {
    if ($value['user_id'] == 2) {
        return true;
    }
});
$filter->all();

search() : Finds the key of a given value or returns false if not found. It supports strict comparison and custom callbacks. Example:

$names = collect(['Alex', 'John', 'Jason', 'Martyn', 'Hanlin']);
$names->search('Jason'); // returns 2

chunk() : Splits a collection into smaller collections of a given size. Example:

$prices = collect([18, 23, 65, 36, 97, 43, 81]);
$prices = $prices->chunk(3)->toArray();

dump() : Dumps the collection for debugging.

map() : Transforms each item using a callback and returns a new collection. Example:

$changed = $collection->map(function($value, $key) {
    $value['user_id'] += 1;
    return $value;
});
$changed->all();

zip() : Merges the collection with another array by index.

whereNotIn() : Filters out items whose given key's value is in the supplied array.

max() : Retrieves the maximum value for a given key.

pluck() : Extracts a single column's values from the collection. Example: $titles = $collection->pluck('title')->all(); each() : Iterates over the collection, executing a callback for each item.

tap() : Passes the collection to a callback without altering the original instance.

pipe() : Sends the collection through a callback and returns the callback's result.

contains() : Checks if a value or key/value pair exists in the collection.

forget() : Removes an item by its key.

avg() (or average): Calculates the average of numeric values for a given key.

These methods allow you to manipulate data efficiently after retrieving it from the database, reducing the need for additional queries.