VB.NET - Array.Find Function

Array.Find. The VB.NET Array.Find Function is available for all arrays. It searches an array. It applies a Predicate method we specify.

Array

The Predicate we pass to Array.Find indicates whether an element matches or not. It returns a Boolean. We demonstrate Array.Find.

Func

An example. First, we use Array.Find with two arguments. The first argument is the array we are searching. And the second is the Predicate definition.

Info We use the lambda expression syntax to specify the predicates. We handle String elements.

Lambda

Next We use the StartsWith Function to test prefixes. We use the Length property to access character counts.

String StartsWith

String Length

Then We also apply the FindAll Function. This is similar to Find, but it returns an array of all the elements found.

Info Find returns only one element. If no matches are found, Nothing is returned.

Nothing

Module Module1 Sub Main() ' Input array. Dim arr() As String = {"cat", "dog", "carrot", "bird"} ' Find element starting with "car". Dim value1 As String = Array.Find(arr, Function(x) (x.StartsWith("car"))) Console.WriteLine(value1) ' Find element of length 3. Dim value2 As String = Array.Find(arr, Function(x) (x.Length = 3)) Console.WriteLine(value2) ' Find all elements of length 4 or less. Dim arr2() As String = Array.FindAll(arr, Function(x) (x.Length <= 4)) Console.WriteLine(String.Join(",", arr2)) End Sub End Module

carrot cat cat,dog,bird

Notes, lambdas. We use the Function keyword to specify a lambda. The first part is the argument to the Function, and the second is the expression that the Function evaluates and returns.

Summary. Arrays can be searched with loops. This often results in more complex code—we must manage arrays, elements and indexes. With Find and FindAll, we eliminate these forms of complexity.

For

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This page was last updated on Mar 10, 2023 (edit).

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