Laravel: Get Object From Collection By Attribute

You can use filter, like so:

$desired_object = $food->filter(function($item) {
    return $item->id == 24;
})->first();

filter will also return a Collection, but since you know there will be only one, you can call first on that Collection.

You don't need the filter anymore (or maybe ever, I don't know this is almost 4 years old). You can just use first:

$desired_object = $food->first(function($item) {
    return $item->id == 24;
});

Laravel provides a method called keyBy which allows to set keys by given key in model.

$collection = $collection->keyBy('id');

will return the collection but with keys being the values of id attribute from any model.

Then you can say:

$desired_food = $foods->get(21); // Grab the food with an ID of 21

and it will grab the correct item without the mess of using a filter function.

As from Laravel 5.5 you can use firstWhere()

In you case:

$green_foods = $foods->firstWhere('color', 'green');

Use the built in collection methods contain and find, which will search by primary ids (instead of array keys). Example:

if ($model->collection->contains($primaryId)) {
    var_dump($model->collection->find($primaryId);
}

contains() actually just calls find() and checks for null, so you could shorten it down to:

if ($myModel = $model->collection->find($primaryId)) {
    var_dump($myModel);
}

Since I don't need to loop entire collection, I think it is better to have helper function like this

/**
 * Check if there is a item in a collection by given key and value
 * @param Illuminate\Support\Collection $collection collection in which search is to be made
 * @param string $key name of key to be checked
 * @param string $value value of key to be checkied
 * @return boolean|object false if not found, object if it is found
 */
function findInCollection(Illuminate\Support\Collection $collection, $key, $value) {
    foreach ($collection as $item) {
        if (isset($item->$key) && $item->$key == $value) {
            return $item;
        }
    }
    return FALSE;
}

I know this question was originally asked before Laravel 5.0 was released, but as of Laravel 5.0, Collections support the where() method for this purpose.

For Laravel 5.0, 5.1, and 5.2, the where() method on the Collection will only do an equals comparison. Also, it does a strict equals comparison (===) by default. To do a loose comparison (==), you can either pass false as the third parameter or use the whereLoose() method.

As of Laravel 5.3, the where() method was expanded to work more like the where() method for the query builder, which accepts an operator as the second parameter. Also like the query builder, the operator will default to an equals comparison if none is supplied. The default comparison was also switched from strict by default to loose by default. So, if you'd like a strict comparison, you can use whereStrict(), or just use === as the operator for where().

Therefore, as of Laravel 5.0, the last code example in the question will work exactly as intended:

$foods = Food::all();
$green_foods = $foods->where('color', 'green'); // This will work.  :)

// This will only work in Laravel 5.3+
$cheap_foods = $foods->where('price', '<', 5);

// Assuming "quantity" is an integer...
// This will not match any records in 5.0, 5.1, 5.2 due to the default strict comparison.
// This will match records just fine in 5.3+ due to the default loose comparison.
$dozen_foods = $foods->where('quantity', '12');

I have to point out that there is a small but absolutely CRITICAL error in kalley's answer. I struggled with this for several hours before realizing:

Inside the function, what you are returning is a comparison, and thus something like this would be more correct:

$desired_object = $food->filter(function($item) {
    return ($item->id **==** 24);
})->first();

Elegant solution for finding a value (http://betamode.de/2013/10/17/laravel-4-eloquent-check-if-there-is-a-model-with-certain-key-value-pair-in-a-collection/) can be adapted:

$desired_object_key = $food->array_search(24, $food->lists('id'));
if ($desired_object_key !== false) {
   $desired_object = $food[$desired_object_key];
}

As the question above when you are using the where clause you also need to use the get Or first method to get the result.

/**
*Get all food
*
*/

$foods = Food::all();

/**
*Get green food 
*
*/

$green_foods = Food::where('color', 'green')->get();

If you have one-to-many relationship in Laravel, you can write simply the following. (for example you have a car manufacturer and car models)

            /** Initialize array */
            $data = [];

            /** Extract collection*/
            foreach (Model::all() as $model) {
                /** Initialize relation model array */
                $relationObjects = [];

                /** Iterate and make associative array */
                foreach ($model->relationObjects as $relObject) {
                    $relationObjects[] = $relObject->name; // name or whatever property you want
                }

                /** Push 'relationObjects' to coresponding 'modelName' key */
                $data[$model->name][] = $relationObjects;
            } 

The $data will be in a form as:

 [   
    "Porsche": [
        [
            "Cayenne",
            "911 GT3"
        ]
    ],
    "Ford": [
        [
            "Mustang"
        ]
    ],
]