linq Standard Query Operators Element Operations
Example
Element operations return a single, specific element from a sequence.
ElementAt
Returns the element at a specified index in a collection.
Method Syntax
// ElementAt
var strings = new string[] { "zero", "one", "two", "three" };
var str = strings.ElementAt(2);
// str = "two"
Query Syntax
// Not Applicable.
ElementAtOrDefault
Returns the element at a specified index in a collection or a default value if the index is out of range.
Method Syntax
// ElementAtOrDefault
var strings = new string[] { "zero", "one", "two", "three" };
var str = strings.ElementAtOrDefault(10);
// str = null
Query Syntax
// Not Applicable.
First
Returns the first element of a collection, or the first element that satisfies a condition.
Method Syntax
// First
var numbers = new int[] { 1, 2, 3, 4, 5 };
var first = strings.First();
// first = 1
Query Syntax
// Not Applicable.
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.
Method Syntax
// FirstOrDefault
var numbers = new int[] { 1, 2, 3, 4, 5 };
var firstGreaterThanTen = strings.FirstOrDefault(n => n > 10);
// firstGreaterThanTen = 0
Query Syntax
// Not Applicable.
Last
Returns the last element of a collection, or the last element that satisfies a condition.
Method Syntax
// Last
var numbers = new int[] { 1, 2, 3, 4, 5 };
var last = strings.Last();
// last = 5
Query Syntax
// Not Applicable.
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.
Method Syntax
// LastOrDefault
var numbers = new int[] { 1, 2, 3, 4, 5 };
var lastGreaterThanTen = strings.LastOrDefault(n => n > 10);
// lastGreaterThanTen = 0
Query Syntax
// Not Applicable.
Single
Returns the only element of a collection, or the only element that satisfies a condition.
Method Syntax
// Single
var numbers = new int[] { 1 };
var single = strings.Single();
// single = 1
Query Syntax
// Not Applicable.
SingleOrDefault
Returns the only element of a collection, or the only element that satisfies a condition. Returns a default value if no such element exists or the collection does not contain exactly one element.
Method Syntax
// SingleOrDefault
var numbers = new int[] { 1, 2, 3, 4, 5 };
var singleGreaterThanFour = strings.SingleOrDefault(n => n > 4);
// singleGreaterThanFour = 5
Query Syntax
// Not Applicable.
