CODEWITHSUNDEEP
vb.net
SQL and Java Learner
SQL and Java Learner

Reputation: 731

How to delete values from array in VB.Net

I have an array that contains these values

{1, 5, 16, 15}

I want to delete the first element so that the values are now.

{Null, 5, 16, 15}

I then want to go through again and delete the first non-null value, which would yield:

{Null, Null, 16, 15}

How do I code this in VB?

Upvotes: 1

Views: 2562

Answers (4)

Chetan Sanghani
Chetan Sanghani

Reputation: 2111

Try this:

Dim strArray() As Integer = {1, 5, 16, 15}
Dim strValues = strArray().ToList
Dim index = 3
strValues = strValues.Where(Function(s) s <> strValues(index)).ToArray

Upvotes: 0

Andrew Morton
Andrew Morton

Reputation: 25023

An Integer in VB.NET is a value type. If you try to set it to Nothing (there is no null in VB.NET) then it takes its default value, which for an Integer is zero.

You can use a Nullable(Of Integer) instead, which can also be written as Integer?.

As a demonstration:

Option Infer On
Option Strict On

Module Module1

    Sub Main()
        Dim myArray As Integer?() = {1, 5, 16, 15}

        For j = 1 To 3

            For i = 0 To UBound(myArray)
                If myArray(i).HasValue Then
                    myArray(i) = Nothing
                    Exit For
                End If
            Next i

            ' show the values...
            Console.WriteLine(String.Join(", ", myArray.Select(Function(n) If(n.HasValue, n.Value.ToString(), "Nothing"))))

        Next

        Console.ReadLine()

    End Sub

End Module

Outputs:

Nothing, 5, 16, 15
Nothing, Nothing, 16, 15
Nothing, Nothing, Nothing, 15

If you are interested in the difference from C# see, e.g., Why can you assign Nothing to an Integer in VB.NET?

Upvotes: 3

HighTechProgramming15
HighTechProgramming15

Reputation: 343

You can use something like this:

Dim myArray(3) As Integer
    myArray(0) = 1
    myArray(1) = 2
    myArray(2) = 3
    myArray(3) = 4
myArray = removeVal(myArray, 2)

-

Function removeVal(ByRef Array() As Integer, ByRef remove As Integer) As Integer()
    Array(remove) = Nothing
    Return Array
End Function

Upvotes: 0

zack.lore
zack.lore

Reputation: 527

Try this

Dim i As Integer

For i = 0 To UBound(myArray)
    If Not IsNothing(myArray(i)) Then
        myArray(i) = Nothing
        Exit For
    End If
Next i

as @Andrew Morton mentioned, a normal Integer value cannot be Null (Nothing). There is a nullable integer type Integer? which can be set to a Null value (Nothing in this case). The above code would only be appropriate if the array was of Integer? values rather than an Integer value.

Upvotes: 3

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