Array Issue not getting expected result

Question

I have a code that should check a list of elements in an array and the resulting list should give me eliminating the repeating values. Here is my code

List <int> ProductListFinalized = new List<int>(ProductIdList);

for(int i = 0 ; i < ProductIdList.Count(); i++) 
{   
    int ProductId = ProductIdList[i];
    Res= !(ProductListFinalized.Contains(ProductId));
    if(!(ProductListFinalized.Contains(ProductId)))
    {
        ProductListFinalized.Add(ProductId); 
    }   
}

ProductIdListForCycleCount = ProductListFinalized.ToArray();

I am still finding the repeating values in the resulting Array. Whats is wrong with my code?

new List<int>(ProductIdList);, you certainly don't want that — Camilo Terevinto
– Camilo Terevinto, Commented May 11, 2018 at 12:05
you can use Distinct : ProductListFinalized.Select(x => x.ProductId).Distinct(); — Vincent Elbert Budiman
– Vincent Elbert Budiman, Commented May 11, 2018 at 12:06

Camilo Terevinto · Accepted Answer · 2018-05-11 12:12:57Z

3

Because List<int> ProductListFinalized = new List<int>(ProductIdList); created a new list with the same values that ProductIdList, so always they'll be contain of list.

You have to create an empty list:

List<int> ProductListFinalized = new List<int>();

edited May 11, 2018 at 12:12

Camilo Terevinto

32.2k7 gold badges95 silver badges127 bronze badges

answered May 11, 2018 at 12:08

FValle

1142 bronze badges

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

Comments

Tatranskymedved · Accepted Answer · 2018-05-11 12:09:50Z

1

At first, You are already entering "all entities" by running this line:

List <int> ProductListFinalized = new List<int>(ProductIdList);

As List will get larger based on needs, You can simply do:

var ProductListFinalized = new List<int>(); //Do not enter parameter here

Also to simplify the running process, You can avoid the C# usage of for, and use a LINQ query Distinct() for the expected results.

var ProductListFinalized = ProductIdList.Distinct();

answered May 11, 2018 at 12:09

Tatranskymedved

4,4313 gold badges29 silver badges51 bronze badges

Comments

Camilo Terevinto · Accepted Answer · 2018-05-11 12:12:18Z

0

As you can read from the docs, List<T>(IEnumerable<T>):

Initializes a new instance of the List<T> class that contains elements copied from the specified collection and has sufficient capacity to accommodate the number of elements copied.

But, you don't want a List<T> here, you want a HashSet<T> instead:

If collection contains duplicates, the set will contain one of each unique element. No exception will be thrown. Therefore, the size of the resulting set is not identical to the size of collection.

So, your entire code could be reduced to just this:

var productListFinalized = new HashSet<int>(ProductIdList);

answered May 11, 2018 at 12:12

Camilo Terevinto

32.2k7 gold badges95 silver badges127 bronze badges

Collectives™ on Stack Overflow

Array Issue not getting expected result

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related