What does LINQ return when the results are empty

Question

I have a question about LINQ query  Normally a query returns a IEnumerable lt T gt  type  If the return is empty  not sure if it is null or not  I am not sure if the following ToList   will throw an exception or just a empty List lt string gt  if nothing found in IEnumerable result        List lt string gt  list     a          is the result null or something else     IEnumerable lt string gt  ilist   from x in list where x     ABC  select x        Or directly to a list  exception thrown     List lt string gt  list1    from x in list where x     ABC  select x  ToList      I know it is a very simple question  but I don t have VS available for the time being

User · Answer

Other posts here have made it clear that the result is an "empty" IQueryable, which ToList() will correctly change to be an empty list etc.

Do be careful with some of the operators, as they will throw if you send them an empty enumerable. This can happen when you chain them together.

User · Answer

var lst   new List lt int gt      1  2  3    var ans   lst Where  i   gt  i  gt  3      ans    null  Dump        False  ans Count      0   Dump        True    Dump is from LinqPad

User · Answer

ToList returns an empty list   same as new List

User · Answer

It won t throw exception  you ll get an empty list

User · Answer

In Linq-to-SQL if you try to get the first element on a query with no results you will get sequence contains no elements error  I can assure you that the mentioned error is not equal to object reference not set to an instance of an object   in conclusion no  it won t return null since null can t say sequence contains no elements it will always say object reference not set to an instance of an object

User · Answer

It will return an empty enumerable  It wont be null  You can sleep sound

User · Answer

You can also check the  Any   method      if   YourResult Any      Just a note that  Any will still retrieve the records from the database  doing a  FirstOrDefault    Where   will be just as much overhead but you would then be able to catch the object s  returned from the query

[c#] What does LINQ return when the results are empty

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