How to find duplicate elements length in array flutter?

Question

I want to implement add to checkout in which number of items added is displayed. Plus button adds elements in list and minus removes elements from list. Goal is just to display particular items added and its quantity. I have added items in list want to count length of duplicate items. How we can do that in flutter?

towhid · Accepted Answer · 2021-09-05 07:47:01Z

7

here is your solution. [Null Safe]

void main() {
  List<int> items = [1, 1, 1, 2, 3, 4, 5, 5];

  Map<int, int> count = {};
  items.forEach((i) => count[i] = (count[i] ?? 0) + 1);

  print(count.toString()); // {1: 3, 2: 1, 3: 1, 4: 1, 5: 2}
}

edited Sep 5, 2021 at 7:47

answered Oct 27, 2020 at 7:26

towhid

3,3088 gold badges20 silver badges31 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

vbakale Over a year ago

But how we can retrieve that length of duplicate item? as you mentioned in your example above there are three '1's and in the output it shows {1:3, ......}. So now i just want to display that 3 here.

towhid Over a year ago

count is a map object. so you can write count['1'] to get its value 3

vbakale Over a year ago

Thank you it solved the question asked but now facing new issue. Whenever i add menu items to cart. The other items quantity also changes. Can we modify above solution for this also?

towhid Over a year ago

The cart list should contain only product items. Why are you adding menu items to the cart? Also, can you share your code sample?

Collectives™ on Stack Overflow

How to find duplicate elements length in array flutter?

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related