Laravel collection contains
Stefan Izdrail
Founder & Senior Architect · 2026-06-29
Title: Understanding Laravel Collection Objects and Using contains() Method Efficiently
Laravel has made working with collections easier through a variety of methods like `filter`, `map`, `reduce`, `sortByDescending`, and more. However, the `contains()` method can sometimes cause confusion for developers who are just getting started or have not extensively used collections in Laravel. In this post, we will dive into the use of the `contains()` method on collections and provide insights to help you better understand its functionality.
Let's start with a simple example to demonstrate how the `contains()` method works on a collection:
```php
use App\Models\Option;
// Given collection of options
$options = collect([
new Option(['id' => 10, 'name' => 'Test A']),
new Option(['id' => 11, 'name' => 'Test B']),
new Option(['id' => 12, 'name' => 'Test C'])
]);
$options->contains(function ($option) {
return $option->id == 10;
}); // returns true
```
In this example, we create a collection of options with different IDs. We then check if the collection contains an option with an `id` of 10 using the custom function provided inside the `contains()` method and display the result. The method is working as expected in this case.
However, when working with nested collections or non-unique values, things can get tricky:
```php
$options = collect([
new Option(['id' => 10, 'name' => 'Test A']),
new Option(['id' => 11, 'name' => 'Test B']),
new Option(['id' => 12, 'name' => 'Test C'])
]);
$results = $options->map(function ($option) {
return [
'id' => $option->id,
'votes' => collect([
new Vote(['value' => 1]),
new Vote(['value' => 2])
])
];
})->groupBy('id'); // Group the options by their IDs
// Given collection of results with an id 10
$resultsWithIdTen = $results['10'];
foreach ($this->options as $option) {
if($options->contains($option->id)) {
dd('test');
}
}
```
In this scenario, we group options by their IDs and then iterate over the original collection of options. However, since there is no way to check a value directly in Laravel with `$options->contains($option->id)`, it causes an error when trying to access an array key of a nested collection:
```php
Error Exception: Undefined offset: 0
```
To avoid this issue, you can either:
- Iterate over each item in the nested collections and check for the existence of the ID manually.
- Flatten your arrays or collections to make them compatible with `contains()`.
In conclusion, when using Laravel's `contains()` method on collections, make sure to consider your data structure and potential pitfalls like nested collections and non-unique values. With proper understanding and implementation techniques, you can successfully take advantage of the power of Laravel collection methods in your applications. Remember to always test your code and use the best approach for each situation.