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

7

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, 2013 at 13:59

almaz

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OJ. · Accepted Answer · 2013-02-02 05:21:02Z

1

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, 2013 at 5:21

OJ.

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2 Answers 2