Element operations (C#)
Element operations return a single, specific element from a sequence.
The standard query operator methods that perform element operations are listed in the following section.
Methods
| Method name | Description | C# query expression syntax | More information |
|---|---|---|---|
| ElementAt | Returns the element at a specified index in a collection. | Not applicable. | Enumerable.ElementAt Queryable.ElementAt |
| ElementAtOrDefault | Returns the element at a specified index in a collection or a default value if the index is out of range. | Not applicable. | Enumerable.ElementAtOrDefault Queryable.ElementAtOrDefault |
| First | Returns the first element of a collection, or the first element that satisfies a condition. | Not applicable. | Enumerable.First Queryable.First |
| FirstOrDefault | Returns the first element of a collection, or the first element that satisfies a condition. Returns a default value if no such element exists. | Not applicable. | Enumerable.FirstOrDefault Queryable.FirstOrDefault Queryable.FirstOrDefault<TSource>(IQueryable<TSource>) |
| Last | Returns the last element of a collection, or the last element that satisfies a condition. | Not applicable. | Enumerable.Last Queryable.Last |
| LastOrDefault | Returns the last element of a collection, or the last element that satisfies a condition. Returns a default value if no such element exists. | Not applicable. | Enumerable.LastOrDefault Queryable.LastOrDefault |
| Single | Returns the only element of a collection or the only element that satisfies a condition. Throws an InvalidOperationException if there is no element or more than one element to return. | Not applicable. | Enumerable.Single Queryable.Single |
| SingleOrDefault | Returns the only element of a collection or the only element that satisfies a condition. Returns a default value if there is no element to return. Throws an InvalidOperationException if there is more than one element to return. | Not applicable. | Enumerable.SingleOrDefault Queryable.SingleOrDefault |
See also
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