2D array summary

So I had to make a 2D array that would append the percentage of change from the previous row to the current row at the end of that row. For example:


50 100 100 50 0.00 0.00 0.00 0.00
50 200 50 25 0.00 100 -50 -50

Now I have this part down but now i need to make it so it creates another row at then end that says the percentage change overall.


here is the code I have so far

Code:

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Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim col As Integer

        Dim rows() As String = IO.File.ReadAllLines("C:\sales.txt")

        Dim All(rows.GetUpperBound(0), rows(0).Split(New String() {Chr(9)}, StringSplitOptions.RemoveEmptyEntries).GetUpperBound(0)) As Decimal

        Dim newRows As New List(Of String)

        For row As Integer = 0 To rows.GetUpperBound(0)

            Dim parts() As String = rows(row).Split(New String() {Chr(9)}, StringSplitOptions.RemoveEmptyEntries)

            newRows.Add(String.Join("  ", parts) & "  ")

            For column As Integer = 0 To parts.GetUpperBound(0)
                col = parts.GetUpperBound(0)
                All(row, column) = CDec(parts(column))

                If row > 0 Then

                    newRows(newRows.Count - 1) &= (((All(row, column) / All(row - 1, column)) * 100) - 100).ToString("n2") & "  "
             
                ElseIf row = 0 AndAlso column = 0 Then

                    Dim d(parts.GetUpperBound(0)) As Decimal

                    newRows(newRows.Count - 1) &= String.Join(" ", Array.ConvertAll(Of Decimal, String)(d, Function(v As Decimal) v.ToString("n2")))

                End If

            Next

        Next

        TextBox1.Lines = newRows.ToArray




        'to save:

        IO.File.WriteAllLines("C:\Solution.txt", newRows.ToArray)

        ' squareArray is the array
        MessageBox.Show("Done!!!")

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Me.Close()

    End Sub
End Class

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Were you here under a different name, or is this a class assignment? I ask because that's a really strange requirement, and you are the second person to ask in as many weeks.

In any case, what is the percentage overall? Is that just the change from the first to the last?

I wasn't here, but it is a class assignment.

yes the change from the first row to the last row.

Here is the "sales.txt" file and the "solution.txt" file that my program creates. But the sales.txt file is subject to change, so the program has to manipulate the data dynamically.

how do you mean 'the percentage change overall'?

Basically the percentage of change between the first and last rows of data in Sales.txt

I can think of doing this in two ways:
-adding all the values in the newly created rows together in each column
-(last row/first row * 100) - 100 for each column



PS: Thank you so much for helping me with this.

i'd use the first method.

put this after the Dim All... line

vb Code:

dim difference(All.GetUpperBound(1)) as decimal

then after the first newRows(newRows.Count - 1) &= line:

vb Code:

difference(column) += (((All(row, column) / All(row - 1, column)) * 100) - 100)

the total percentage differences will be in the difference array + i'm sure you'll be able to work out how to add it to the newrows list before you write your new file.

at least you admitted this is homework:D that guy last week forgot to mention it...

It's saying that the change in column one is -34.38... I don't get it.

Quote:

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Originally Posted by aLittleBunny

It's saying that the change in column one is -34.38... I don't get it.

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that looks ok to me. if you add all the percentage changes for column1, that would be the answer. don't forget 100 + -50 = 50

But if you do the manual change in difference it is only -18.52

(25.73/36.99) * 100 -100

i double checked it. here's a test of the 2 methods side by side + there is a slight variation, though i'm not sure why:

vb Code:

Dim change = (From line In IO.File.ReadAllLines("Solution.txt") _
                      Let fields = line.Split(New String() {Chr(32)}, StringSplitOptions.RemoveEmptyEntries) _
                      Select CDec(fields(7))).Sum
Dim lines() As String = IO.File.ReadAllLines("Solution.txt")
Dim change2 As Decimal = ((CDec(lines(lines.GetUpperBound(0)).Split(New String() {Chr(32)}, StringSplitOptions.RemoveEmptyEntries)(0)) / CDec(lines(0).Split(New String() {Chr(32)}, StringSplitOptions.RemoveEmptyEntries)(0))) * 100) - 100

I am still getting the same problem...
Rather than getting the overall percentage change for each column I'm getting -34.41

Code:

---

Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim col As Integer

        Dim rows() As String = IO.File.ReadAllLines("C:\sales.txt")

        Dim All(rows.GetUpperBound(0), rows(0).Split(New String() {Chr(9)}, StringSplitOptions.RemoveEmptyEntries).GetUpperBound(0)) As Decimal

        Dim newRows As New List(Of String)

        For row As Integer = 0 To rows.GetUpperBound(0)

            Dim parts() As String = rows(row).Split(New String() {Chr(9)}, StringSplitOptions.RemoveEmptyEntries)

            newRows.Add(String.Join("  ", parts) & "  ")

            For column As Integer = 0 To parts.GetUpperBound(0)
                col = parts.GetUpperBound(0)
                All(row, column) = CDec(parts(column))

                If row > 0 Then

                    newRows(newRows.Count - 1) &= (((All(row, column) / All(row - 1, column)) * 100) - 100).ToString("n2") & "  "
             
                ElseIf row = 0 AndAlso column = 0 Then

                    Dim d(parts.GetUpperBound(0)) As Decimal

                    newRows(newRows.Count - 1) &= String.Join(" ", Array.ConvertAll(Of Decimal, String)(d, Function(v As Decimal) v.ToString("n2")))

                End If

            Next

        Next

        TextBox1.Lines = newRows.ToArray





        'to save:

        IO.File.WriteAllLines("C:\Solution.txt", newRows.ToArray)


        Dim change = (From line In IO.File.ReadAllLines("C:\Solution.txt") Let fields = line.Split(New String() {Chr(32)}, StringSplitOptions.RemoveEmptyEntries) Select CDec(fields(7))).Sum


        TextBox1.AppendText(vbCrLf & change)

        'Dim lines() As String = IO.File.ReadAllLines("C:\Solution.txt")

        '  Dim change2 As Decimal = ((CDec(lines(lines.GetUpperBound(0)).Split(New String() {Chr(32)}, StringSplitOptions.RemoveEmptyEntries)(0)) / CDec(lines(0).Split(New String() {Chr(32)}, StringSplitOptions.RemoveEmptyEntries)(0))) * 100) - 100.ToString("n2") & "  "




        ' Dim WriteSolution As System.IO.StreamWriter
        ' WriteSolution = System.IO.File.AppendText("C:\Solution.txt")
        'WriteSolution.WriteLine(TextBox1.Text)
        'WriteSolution.Close()


        IO.File.WriteAllLines("C:\Solution.txt", TextBox1.Text)

        MessageBox.Show("Done!!!")

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Me.Close()

    End Sub
End Class

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I also don't know why I get:
"Value of type 'String' cannot be converted to '1-dimensional array of String'."

When i try the uncommented out method of writing to the text file.

vb Code:

IO.File.WriteAllLines("C:\Solution.txt", TextBox1.lines)

or:

vb Code:

IO.File.WriteAlltext("C:\Solution.txt", TextBox1.Text)

Got it

Code:

---

Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim col As Integer
        '  Dim lengthof As Integer
        Dim rows() As String = IO.File.ReadAllLines("C:\sales.txt")

        Dim All(rows.GetUpperBound(0), rows(0).Split(New String() {Chr(9)}, StringSplitOptions.RemoveEmptyEntries).GetUpperBound(0)) As Decimal

        Dim difference(All.GetUpperBound(1)) As Decimal

        Dim newRows As New List(Of String)

        For row As Integer = 0 To rows.GetUpperBound(0)

            Dim parts() As String = rows(row).Split(New String() {Chr(9)}, StringSplitOptions.RemoveEmptyEntries)

            newRows.Add(String.Join("  ", parts) & "  ")

            For column As Integer = 0 To parts.GetUpperBound(0)
                col = parts.GetUpperBound(0)
                All(row, column) = CDec(parts(column))

                If row > 0 Then

                    newRows(newRows.Count - 1) &= (((All(row, column) / All(row - 1, column)) * 100) - 100).ToString("n2") & "  "
                    difference(column) += (((All(row, column) / All(row - 1, column)) * 100) - 100).ToString("n2") & "  "

                ElseIf row = 0 AndAlso column = 0 Then

                    Dim d(parts.GetUpperBound(0)) As Decimal

                    newRows(newRows.Count - 1) &= String.Join(" ", Array.ConvertAll(Of Decimal, String)(d, Function(v As Decimal) v.ToString("n2")))

                End If

            Next

        Next

        TextBox1.Lines = newRows.ToArray
        TextBox1.AppendText(vbCrLf)

        For count As Integer = 0 To difference.Length - 1


            TextBox1.AppendText(difference(count) & "    ")


        Next

        'to save:

        IO.File.WriteAllText("C:\Solution.txt", TextBox1.Text)



        MessageBox.Show("Done!!!")

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Me.Close()

    End Sub
End Class

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think it through. All(,) is a decimal, difference() is a decimal, so to add a decimal element + a decimal element, why convert 1 of those values to a string?

vb Code:

difference(column) += (((All(row, column) / All(row - 1, column)) * 100) - 100).ToString("n2")