Sum of value in a collection using flutter

Question

I have a list/collection and I need to get the sum of all prices in this list.

cart_items = [
    {
        "id": 144,
        "created_at": "2019-04-04 14:42:04",
        "updated_at": "2019-04-04 14:42:04",
        "cart_id": "3",
        "client_id": "83",
        "product_id": "6",
        "quantity": "1",
        "price": "1500",
        "name": "Cucumber (2Pcs)",
        "image": "products/es4eGjkgQ6MvzTaMyX4iXWjcSX03mVk3QB9oODWk.jpeg",
       },
    {
        "id": 145,
        "created_at": "2019-04-04 14:42:09",
        "updated_at": "2019-04-04 14:42:09",
        "cart_id": "3",
        "client_id": "83",
        "product_id": "5",
        "quantity": "1",
        "price": "2000",
        "name": "Cauliflower",
        "image": "products/lVZ31zORzltyVIDXhHoCWUgjTlal7cWd7pI8DL2V.jpeg",
        }
]

I have been trying to use the reduce method on this collection/list but I don't know how to specify that I need to get the sum for price.

Harsh Bhikadia · Accepted Answer · 2021-02-19 08:20:53Z

17

Here you go:

cart_items.map<int>((m) => int.parse(m["price"])).reduce((a,b )=>a+b)

As @user3612643 pointed out in comment, this does not work if the collection is empty, so condition check for it required in that case.

edited Feb 19, 2021 at 8:20

answered Apr 4, 2019 at 16:01

Harsh Bhikadia

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5 Comments

Harsh Bhikadia Over a year ago

could you also upvote the answer, if it is what you were looking for.

Basudev Nayak Over a year ago

This did not solve the issue, I am getting the result separately. refer here: stackoverflow.com/questions/65644043/…

user3612643 Over a year ago

Breaks if the collection is empty.

Harsh Bhikadia Over a year ago

@user3612643 Thanks for pointing this out. Will put this in answere

tmaihoff Over a year ago

For the sake of completeness: In 2021 you can replace the reduce((a,b)=>a+b) part by just calling .sum on the list. Just import import 'package:collection/collection.dart'; first

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