Add count of duplicate values to Laravel collection

Question

I don´t want to remove the duplicate values, I want to get the articles_id duplicates and sum their quantity values, for example, this is my collection:

Collection {#306 ▼
  #items: array:3 [▼
    0 => CartLine {#294 ▼
      +quantity: 2
      +article_id: 1728
      +article_name: "TAZA CERAMICA"
    }
    1 => CartLine {#296 ▼
      +parent_line_id: null
      +quantity: 1
      +article_id: 1728
      +article_name: "TAZA CERAMICA"
    }
    2 => CartLine {#298 ▼
      +quantity: 1
      +article_id: 1378
      +article_name: "JARRA CERVEZA ALEMANA"

    }
  ]
}

And I want get this result:

Collection {#306 ▼
  #items: array:3 [▼
    0 => CartLine {#294 ▼
      +quantity: 3 //sum total quantity of the duplicates elements with same article_id
      +article_id: 1728
      +article_name: "TAZA CERAMICA"
    }
    1 => CartLine {#296 ▼
      +parent_line_id: null
      +quantity: 3
      +article_id: 1728
      +article_name: "TAZA CERAMICA"
    }
    2 => CartLine {#298 ▼
      +quantity: 1
      +article_id: 1378
      +article_name: "JARRA CERVEZA ALEMANA"

    }
  ]
}

I want sum the quantities of the duplicate elements and set the quantity property with the sum in these elements.

Answer 1

You could try something like:

$collection->groupBy('article_id')->flatMap(function ($items) {

    $quantity = $items->sum('quantity');

    return $items->map(function ($item) use ($quantity) {

        $item->quantity = $quantity;

        return $item;

    });

});

Obviously, change $collection to be whatever you've called the variable that holds your collection.

Hope this helps!