Aggregation
Aggregate, Average, Count, LongCount, Max, Min, Sum
Conversion
AsEnumerable, Cast, OfType, ToArray, ToDictionary, ToList, ToLookup
Element
ElementAt, ElementAtOrDefault, First, FirstOrDefault, Last, LastOrDefault, Single, SingleOrDefault
ElementAt
ElementAtOrDefault
First (simple)
First (conditional)
FirstOrDefault
Last
LastOrDefault (simple)
LastOrDefault (conditional)
Single
SingleOrDefault
Generation
DefaultIfEmpty, Empty, Range, Repeat
Grouping
GroupBy
Join
GroupJoin, Join
Ordering
OrderBy, OrderByDescending, Reverse, ThenBy, ThenByDescending
OrderBy (simple - numbers)
OrderBy (simple - dates)
OrderBy (simple - objects)
OrderByDescending
Reverse
ThenBy
ThenByDescending
Other
Concat, SequenceEqual, Zip
Partitioning
Skip, SkipWhile, Take, TakeWhile
Projection
Select, SelectMany
Quantifiers
All, Any, Contains
Restriction
Where
Set
Distinct, Except, Intersect, Union
Close
DefaultIfEmpty: If a collection is empty, its default value is returned. Default value depends on collection type. A default value may be specified.
| DefaultIfEmpty: If a collection is empty, its default value is returned. Default value depends on collection type. A default value may be specified. |
| DefaultIfEmpty: If a collection is empty, its default value is returned. Default value depends on collection type. A default value may be specified. |
| This Lambda Expression sample returns specified default value of 5 for empty array. |
| This Lambda Expression sample returns specified default value of 5 for empty array. |
// A Query Expression cannot be constructed for DefaultIfEmpty() in C#. // Consider using a Lambda Expression instead.
' A Query Expression cannot be constructed for DefaultIfEmpty() in VB.NET. ' Consider using a Lambda Expression instead.
// A Query Expression cannot be constructed for DefaultIfEmpty() in F#. // Consider using a Lambda Expression instead.
static void Sample_DefaultIfEmpty_Lambda_DefaultValue()
{
int[] empty = { };
var result = empty.DefaultIfEmpty(5);
Debug.WriteLine("result contains one element with a value of 5:");
Debug.WriteLine(result.Count() == 1 && result.First() == 5);
}
Output: result contains one element with a value of 5: True
Private Shared Sub Sample_DefaultIfEmpty_Lambda_DefaultValue()
Dim empty As Integer() = {}
Dim result = empty.DefaultIfEmpty(5)
Debug.WriteLine("result contains one element with a value of 5:")
Debug.WriteLine(result.Count() = 1 AndAlso result.First() = 5)
End Sub
Output: result contains one element with a value of 5: True
let Sample_DefaultIfEmpty_Lambda_DefaultValue() =
let empty = []
let result = empty.DefaultIfEmpty(5)
Debug.WriteLine(sprintf "result contains one element with a value of 5:")
Debug.WriteLine(sprintf "%b" (result.Count() = 1 && result.First() = 5))
Output: result contains one element with a value of 5: true