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Enumerable.Any<TSource> Method (IEnumerable<TSource>, Func<TSource, Boolean>)

Silverlight

Other Versions

Determines whether any element of a sequence satisfies a condition.

Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)

Syntax

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public static bool Any<TSource>(
	this IEnumerable<TSource> source,
	Func<TSource, bool> predicate
)

Type Parameters

TSource: The type of the elements of source.

Parameters

source: Type: System.Collections.Generic.IEnumerable<TSource>
An IEnumerable<T> whose elements to apply the predicate to.

predicate: Type: System.Func<TSource, Boolean>
A function to test each element for a condition.

Return Value

Type: System.Boolean
true if any elements in the source sequence pass the test in the specified predicate; otherwise, false.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable<TSource>. When you use instance method syntax to call this method, omit the first parameter.

Exceptions

Exception	Condition
ArgumentNullException	source or predicate is null.

Remarks

Note:
This method does not return any one element of a collection. Instead, it determines whether any elements of a collection satisfy a condition.

The enumeration of source is stopped as soon as the result can be determined.

In Visual Basic query expression syntax, an Aggregate Into Any() clause translates to an invocation of Any.

Examples

The following code example demonstrates how to use Any to determine whether any element in a sequence satisfies a condition.

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      class Pet
      {
         public string Name { get; set; }
         public int Age { get; set; }
         public bool Vaccinated { get; set; }
      }

      public static void AnyEx3()
      {
         // Create an array of Pets.
         Pet[] pets =
                 { new Pet { Name="Barley", Age=8, Vaccinated=true },
                   new Pet { Name="Boots", Age=4, Vaccinated=false },
                   new Pet { Name="Whiskers", Age=1, Vaccinated=false } };

         // Determine whether any pets over age 1 are also unvaccinated.
         bool unvaccinated =
             pets.Any(p => p.Age > 1 && p.Vaccinated == false);

         outputBlock.Text += String.Format(
             "There {0} unvaccinated animals over age one.",
             unvaccinated ? "are" : "are not any") + "\n";
      }

      // This code produces the following output:
      //
      //  There are unvaccinated animals over age one.