linq distinct example

Example 1: C# .NET Core linq Distinct

var distinctUsers = allUsers
    .GroupBy(x => x.UserId)
    .Select(x => x.First())
    .ToList();

Example 2: query DISTINCT

SELECT DISTINCT Column_name FROM table_name;

Example 3: c# distinct comparer multiple properties

public static IEnumerable DistinctBy
    (this IEnumerable source, Func keySelector)
{
    HashSet seenKeys = new HashSet();
    foreach (TSource element in source)
    {
        if (seenKeys.Add(keySelector(element)))
        {
            yield return element;
        }
    }
}

Example 4: linq distinct

var uniquePeople = from p in people
                   group p by new {p.ID} //or group by new {p.ID, p.Name, p.Whatever}
                   into mygroup
                   select mygroup.FirstOrDefault();

Tags:

Misc Example

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