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Laravel: Get Object From Collection By Attribute

Posted by: admin November 1, 2017 Leave a comment

Questions:

In Laravel, if I perform a query:

$foods = Food::where(...)->get();

…then $foods is an Illuminate Collection of Food model objects. (Essentially an array of models.)

However, the keys of this array are simply:

[0, 1, 2, 3, ...]

…so if I want to alter, say, the Food object with an id of 24, I can’t do this:

$desired_object = $foods->get(24);
$desired_object->color = 'Green';
$desired_object->save();

…because this will merely alter the 25th element in the array, not the element with an id of 24.

How do I get a single (or multiple) element(s) from a collection by ANY attribute/column (such as, but not limited to, id / color / age / etc.)?

Of course, I can do this:

foreach ($foods as $food) {
    if ($food->id == 24) {
        $desired_object = $food;
        break;
    }
}
$desired_object->color = 'Green';
$desired_object->save();

…but, that’s just gross.

And, of course, I can do this:

$desired_object = Food::find(24);
$desired_object->color = 'Green';
$desired_object->save();

…but that’s even more gross, because it performs an additional unnecessary query when I already have the desired object in the $foods collection.

Thanks in advance for any guidance.

EDIT:

To be clear, you can call ->find() on an Illuminate Collection without spawning another query, but it only accepts a primary ID. For instance:

$foods = Food::all();
$desired_food = $foods->find(21);  // Grab the food with an ID of 21

However, there is still no clean (non-looping, non-querying) way to grab an element(s) by an attribute from a Collection, like this:

$foods = Food::all();
$green_foods = $foods->where('color', 'green'); // This won't work.  :(
Answers:

You can use filter (under Support), 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.

Questions:
Answers:

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.

Questions:
Answers:

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;
}

Questions:
Answers:

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);
}

Questions:
Answers:

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();

Questions:
Answers:

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');

Questions:
Answers:

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];
}

Questions:
Answers:

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();