Removing duplicate numbers in listbox

[tstory28]

I have been working on a pythagorean theorem calculator and am actually stuck on the final bit of code. What I am trying to do is check the values (integers) inside a listbox, remove duplicate number (both values), and input one of the values into a textbox.

Here is an example of what I am doing:

LISTBOX VALUES
2
2
3
5
5
7

When the program runs, check listbox value #1 and listbox value #2, if listbox value #1 and #2 match (2 & 2), input that value (not both duplicates) into a variable, remove both of the duplicate values, continue checking the rest of the values, and finally multiply the leftover values. I am sure that sounds confusing. Here is what the final output will look like

LISTBOX VALUES
3
7

Variable1 = 2 * 5
Variable2 = 3 * 7

I am sorry if that is difficult but I cannot figure out the proper syntax to get it working.

Thanks in advance for any help.

[Mitja Bonca]

And whai in case if you have numbers:
2,2,2,3,3,3,4

[tstory28]

In that case, just the listbox would look as follows:

2 - (Removed)
2 - (Removed)
2
3 - (Removed)
3 - (Removed)
3
4

Variable1 = 2 * 3
Variable2 = 2 * 3 * 4

[Mitja Bonca]

I did a code, but according to your last example this is not just it:

Take a look:

Public Sub New()
	InitializeComponent()
	listBox1.Items.AddRange(New Object() {2, 2, 3, 5, 5, 7})
End Sub

Private Sub button1_Click(sender As Object, e As EventArgs)
	Dim list As New List(Of Integer)()

	For i As Integer = 0 To listBox1.Items.Count - 1
		Dim value1 As Integer = Integer.Parse(listBox1.Items(i).ToString())
		For j As Integer = i + 1 To listBox1.Items.Count - 1
			Dim value2 As Integer = Integer.Parse(listBox1.Items(j).ToString())
			If value1 = value2 Then
				list.Add(value1)
				RemoveItems(value1)
			End If
		Next
	Next

	'for the end, you do the math operations over the values:
	Dim result1 As Integer = 1
	For Each number As Integer In list
		result1 *= number
	Next
	Dim result2 As Integer = 1
	For i As Integer = 0 To listBox1.Items.Count - 1
		result2 *= Integer.Parse(listBox1.Items(i).ToString())
	Next

	MessageBox.Show("Variable 1 = " & result1 & vbLf & "Variable 2 = " & result2)
End Sub

Private Sub RemoveItems(value As Integer)
	For i As Integer = 0 To listBox1.Items.Count - 1
		listBox1.Items.Remove(value)
	Next
End Sub

[Mitja Bonca]

2 - (Removed) 2 - (Removed) 2 3 - (Removed) 3 - (Removed) 3 4

If I understood, it should be like that:
Variable1 = 2 * 3
Variable2 = 3 (only 3 left)

----------------------------------
In your upper example there were 3 and 7 left, and you multiplay them and got 21!

[tstory28]

Ok... The listbox is going to be populated via a loop. The numbers in the listbox are going to be prime factors, e.g. 312 will populate listbox with 2, 2, 2, 3, 13.

Listbox Values
2
2
2
3
13

When you run the next (For, If, whatever the proper syntax is) block of code, it will check the listbox value #1 (2) against listbox value #2 (2).

If they are the same, input value #1 into a variable and then remove value #1 and value #2 from the listbox.

Listbox Values
2
3
13

Variable1 = 2

Then the listbox will be left with 2, 3, 13. Once again, check value #1 (2) and value #2 (3) to see if they are equal. Since they are not equal, input value #1 (2) into a separate variable.

Listbox Values
2
3
13

Variable1 = 2
Variable2 = 2

Move on and check value #2 (3) and value #3 (13). Since they are not equal, input value #2 into Variable2 and move on.

Listbox Values
2
3
13

Variable1 = 2
Variable2 = 2 * 3

Check value #3 (13) and next value (No value). Since no value #4, input value #3 into Variable2.

Variable1 = 2
Variable2 = 2 * 3 * 13

I hope this explains what I am trying to do better.

[Unhnd_Exception]

Heres another version.

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'Use linq to get the non duplicated list
        Dim Distinct = From Num In ListBox1.Items _
                       Distinct

        'Copy the distinct list of numbers
        Dim Items() As Object = Distinct.ToArray

        'Clear the listbox and add all the numbers except the 
        'first number.
        ListBox1.Items.Clear()
        ListBox1.Items.AddRange(Items.Skip(1).ToArray)

        If Items.Length > 0 Then
            'Get the first number in the list that is not
            'in the textbox.
            Dim FirstInList As Integer = CInt(Items(0))
            Dim TheRemaining As Integer
            For i = 1 To UBound(Items)
                'Multiply all the remaining numbers in the listbox
                'To the first number
                TheRemaining = CInt(FirstInList * CInt(Items(i)))
            Next
        End If

    End Sub

[Mitja Bonca]

O`right, this will do it:

Public Sub New()
	InitializeComponent()
	listBox1.Items.AddRange(New Object() {2, 2, 2, 3, 13})
End Sub

Private Sub button2_Click(sender As Object, e As EventArgs)
	Dim list As New List(Of Integer)()
	For i As Integer = 0 To listBox1.Items.Count - 1
		Dim value1 As Integer = Integer.Parse(listBox1.Items(i).ToString())
		For j As Integer = i + 1 To listBox1.Items.Count - 1
			Dim value2 As Integer = Integer.Parse(listBox1.Items(j).ToString())
			If value1 = value2 Then
				list.Add(value1)
				RemoveItems(value1, i, j)
			End If
		Next
	Next

	'for the end, you do the math operations over the values:
	Dim result1 As Integer = 1
	For Each number As Integer In list
		result1 *= number
	Next
	Dim result2 As Integer = 1
	For i As Integer = 0 To listBox1.Items.Count - 1
		result2 *= Integer.Parse(listBox1.Items(i).ToString())
	Next

	MessageBox.Show("Variable 1 = " & result1 & vbLf & "Variable 2 = " & result2)
End Sub

Private Sub RemoveItems(value As Integer, a As Integer, b As Integer)
	For i As Integer = 0 To listBox1.Items.Count - 1
		If i = a Then
			listBox1.Items.RemoveAt(a)
		ElseIf i = b Then
			listBox1.Items.RemoveAt(b)
		End If
	Next
End Sub

Let me know if its working (it does here).

[Unhnd_Exception]

I read the post wrong. My post is not what your looking for :(

[Unhnd_Exception]

Actually

After reading over the original post again, What does this have to do with a Pythag Thereom.

Private Function GetLength(ByVal sideA As Double, ByVal sideB As Double)
   Return Math.Sqrt(Math.Pow(sideA, 2) + Math.Pow(sideB, 2))
End Function

What does all this list box removal and reading have to do with 2 numbers?

I haven't seen one instance of the pythag thereom in it.

[P.manidas]

Try this one

Dim Complete As Boolean = False
Dim Com As Boolean= False
Dim PlaceNum As String
Dim i As Integer
Dim j As Integer

Dim Num1 As Integer=1
Dim Num2 As Integer=1


Do While Complete = False
If listbox1.Items.Count > 1 Then
For j = 0 To listbox1.Items.Count - 2 Step 1
    PlaceNum = listbox1.Items(j)
    For i = j + 1 To listbox1.Items.Count - 1 Step 1
        If PlaceNum = listbox1.Items (i) Then
            Num1 = Num1 * Val(listbox1.Items (i))
            listbox1.items.RemoveAt (i)
            listbox1.items.RemoveAt (j)
            Complete = False
            Com = True
            Exit For
        Else
            Com = False
        End If
     Next i
     
     If listbox1.Items.Count = 1 Then
     Complete = True
     Exit For
     End If
     
     If Com = True Then
        Exit For
     End If
     
     If j = listbox1.Items.Count - 2 Then
        Complete = True
     End If
Next j
Else
Complete = True
End If
Loop

For i = 0 To listbox1.Items.Count - 1 Step 1
Num2 = Num2 * listbox1.Items (i)
Next i

Textbox1.Text = Num1
Textbox2.Text = Num2

[tstory28]

The only reason I am using the listboxes and remove is because I want the unknown value to come out as 3 (sqrt) 2 instead of (sqrt) 18.