Optimizing a distinction code

Question

List<int> types = new List<int>();
foreach (var d in myTableList)
{
    if (!types.Contains((int)d.item_type))
        types.Add((int)d.item_type);
}

I have a table in db called myTable. There is a column in it called item_type. It is integer.

I want to make a list which would have all item_type which are in myTableList, but there shouldn't be duplicates.

I tried:

types = myTableList.Distinct(x => x.item_type)

but I want types to be list of integers, not items of type myTable.

almaz · Accepted Answer · 2013-01-30 13:59:15Z

up vote 7 down vote accepted

Try

types = myTableList
    .Select(x => (int)x.item_type)
    .Distinct();

You may also want to add .ToList() at the end if you want to match original code

answered Jan 30 at 13:59

almaz
4,864120

OJ. · Answer 2 · 2013-02-02 05:21:02Z

up vote 1 down vote

Another option is to just use a HashSet<T> to do the distinction for you:

var types = new HashSet<int>(myTableList.Select(x => (int)x.item_type)).ToList();

answered Feb 2 at 5:21

OJ.
30017

Distinct does exactly that – almaz Feb 2 at 9:21

Just to expand my previous comment... Distinct uses HashSet to ensure uniqueness of elements, and outputs element if it has not been seen before. – almaz Feb 2 at 10:10

Yes, hence why I said "another option". – OJ. Feb 2 at 22:16

asked	9 months ago
viewed	79 times
active	9 months ago

Optimizing a distinction code

2 Answers

Your Answer

Not the answer you're looking for? Browse other questions tagged c# linq entity-framework or ask your own question.

Community Bulletin

Optimizing a distinction code

2 Answers

Your Answer

Sign up or login

Post as a guest

Not the answer you're looking for? Browse other questions tagged c# linq entity-framework or ask your own question.

Community Bulletin

Related