Laravel 5 Collections: Reducing a Collection With User-Defined Keys With mapWithKeys

The mapWithKeys is similar to the mapToDictionary and mapToGroups methods in that it accepts a $callback function that defines an association between the returned key and value.

The mapWithKeys method does not change the original collection; it will return a new collection instance.

#Signature

1public function mapWithKeys(
2    callable $callback
3);

#Example Use

The following example demonstrates the basic usage of the mapWithKeys method. The example will take a collection of products and return a collection of each of the products and their associated prices:

 1$products = collect([
 2    [
 3        'name'   => 'Office Chair',
 4        'price'  => 399.99,
 5        'onSale' => false
 6    ],
 7    [
 8        'name'   => 'Desk',
 9        'price'  => 199.34,
10        'onSale' => true
11    ]
12]);
13
14$productPrices = $products
15    ->mapWithKeys(function ($item) {
16       return [$item['name'] => $item['price']];
17    });

After the above code has executed, the $productPrices collection would contain values similar to the following output:

1Collection {
2  #items: array [
3    "Office Chair" => 399.99
4    "Desk"         => 199.34
5  ]
6}

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