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FirstOrDefault behavior directly in LINQ statement

Tags:

linq

Seems like I may have missed something simple in the syntax, but I'd like to get the results of FirstOrDefault from a linq statement directly without having to store the IEnumerable in a temporary variable first. Something like this:

var bestCar = from c in cars
              orderby c.Price
              select first c

I know the first keyword doesn't actually exist but illustrates what I'd like to do. I also know I can wrap the from...select statement in parenthesis and call FirstOrDefault directly but I think the above syntax is cleaner and easier to read.

like image 940
Paul Alexander Avatar asked Oct 07 '09 21:10

Paul Alexander


People also ask

What is the use of FirstOrDefault in Linq?

Use the FirstorDefault() method to return the first element of a sequence or a default value if element isn't there. List<double> val = new List<double> { }; Now, we cannot display the first element, since it is an empty collection. For that, use the FirstorDefault() method to display the default value.

What is FirstOrDefault in Linq C#?

In LINQ, FirstOrDefault() Operator is used to return the first element from the list/collection. FirstOrDefault() Operator is same as LINQ First() Operator and the only difference is, in case if the lists returns no elements then LINQ FirstOrDefault operator method will return default value.

What is the difference between first () and FirstOrDefault () Select method in Linq?

The major difference between First and FirstOrDefault is that First() will throw an exception if there is no result data for the supplied criteria whereas FirstOrDefault() will return the default value (null) if there is no result data.

Does FirstOrDefault execute query?

All standard Linq operators, which return single, non-enumerable result, are executed immediately at the point where query is declared. So, FirstOrDefault , Count , Sum and other operators which return single value are executed immediately.


2 Answers

Enumerable.FirstOrDefault is one of the extension methods in the Enumerable class which does not have a corresponding LINQ syntax element. The only way to bind to this method is via method call syntax.

You can avoid the temporary by doing the follownig

var bestCar = (from c in cars
              orderby c.Price
              select c).FirstOrDefault();
like image 148
JaredPar Avatar answered Sep 24 '22 14:09

JaredPar


There isn't a way to do that. LINQ is used for defining a query. Doing that doesn't actually cause an evaluation, whereas executing FirstOrDefault (or enumerating over it) executes the query.

like image 44
Adam Robinson Avatar answered Sep 20 '22 14:09

Adam Robinson



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