You want the Except operator. var answer = list1.Except(list2); Better explanation here: https://docs.microsoft.com/archive/blogs/charlie/linq-farm-more-on-set-operators NOTE: This technique works best for primitive types only, since you have to implement an IEqualityComparer to use the Except method with complex types.
var distinctItems = items.GroupBy(x => x.Id).Select(y => y.First());
It will return an empty enumerable. It won’t be null. You can sleep sound 🙂
Try SelectMany() var result = iList.SelectMany( i => i );
This answer shows usage of LINQ (Aggregate) as requested in the question and is not intended for everyday use. Because this does not use a StringBuilder it will have horrible performance for very long sequences. For regular code use String.Join as shown in the other answer Use aggregate queries like this: string[] words = { … Read more
I examined the methods of System.Linq.Enumerable, discarding any that returned non-IEnumerable results. I checked the remarks of each to determine how the order of the result would differ from order of the source. Preserves Order Absolutely. You can map a source element by index to a result element AsEnumerable Cast Concat Select ToArray ToList Preserves … Read more
var consolidatedChildren = from c in children group c by new { c.School, c.Friend, c.FavoriteColor, } into gcs select new ConsolidatedChild() { School = gcs.Key.School, Friend = gcs.Key.Friend, FavoriteColor = gcs.Key.FavoriteColor, Children = gcs.ToList(), }; var consolidatedChildren = children .GroupBy(c => new { c.School, c.Friend, c.FavoriteColor, }) .Select(gcs => new ConsolidatedChild() { School = gcs.Key.School, … Read more
Try using the ToDictionary method like so: var dict = TableObj.Select( t => new { t.Key, t.TimeStamp } ) .ToDictionary( t => t.Key, t => t.TimeStamp );
.Where(oh => oh.Hierarchy.Contains(“/12/”)) You can also use .StartsWith() or .EndsWith().
myCars.Select((v, i) => new {car = v, index = i}).First(myCondition).index; or the slightly shorter myCars.Select((car, index) => new {car, index}).First(myCondition).index; or the slightly shorter shorter myCars.Select((car, index) => (car, index)).First(myCondition).index;