Array.Find Function
This page was last reviewed on Mar 10, 2023.
Dot Net Perls
Array.Find. The VB.NET Array.Find Function is available for all arrays. It searches an array. It applies a Predicate method we specify.
The Predicate we pass to Array.Find indicates whether an element matches or not. It returns a Boolean. We demonstrate Array.Find.
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.
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.
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.
Dot Net Perls is a collection of tested code examples. Pages are continually updated to stay current, with code correctness a top priority.
Sam Allen is passionate about computer languages. In the past, his work has been recommended by Apple and Microsoft and he has studied computers at a selective university in the United States.
This page was last updated on Mar 10, 2023 (edit).
© 2007-2024 Sam Allen.