Combine multiple txt files alternately (vb.net) - vb.net

Question

Let me explain it on an excel sheet. I have few txt files in directory (f.txt, d.txt, s.txt, a.txt and q.txt). Each file has few lines of text. And I want to combine those files but in specific way - it is shown on screenshot.
and output should be:
I've already made a code but it doesn't work - I don't know why.
Dim fileEntries As String() = Directory.GetFiles("D:\dir\", "*.txt")
' Process the list of .txt files found in the directory. '
Dim i As Integer = 0
Dim filesCount As Integer = Directory.GetFiles("D:\dir\", "*.txt").Count
Do Until i = filesCount
'do it for every file in folder'
i = i + 1
Dim reader As New System.IO.StreamReader(fileEntries(i))
Dim files() As String = reader.ReadToEnd.Split({Environment.NewLine}, StringSplitOptions.RemoveEmptyEntries)
Dim lineCount = File.ReadAllLines(fileEntries(i)).Length
Dim w As Integer = 0
Dim dt As DataTable
dt.Columns.Add(i)
'add column "0" for file 1, "1" for file 2 etc.'
Do Until w = lineCount
dt.Rows.Add(files(w))
'write each line in file 1 to column 0, etc.'
w = w + 1
Loop
Loop
Can somebody help me?

Answer 1

Read/write
If your goal is as shown in the last image, write back to a file named output.txt, then this can be done in a single line of code.
My.Computer.FileSystem.WriteAllText("D:\dir\output.txt", String.Join(Environment.NewLine, (From path As String In Directory.GetFiles("D:\dir", "*.txt") Where IO.Path.GetFileNameWithoutExtension(path) <> "output" Select My.Computer.FileSystem.ReadAllText(path, Encoding.UTF8))), False, Encoding.UTF8)
You can of course make this a bit more readable if you don't like one-liners.
My.Computer.FileSystem.WriteAllText(
"D:\dir\output.txt",
String.Join(
Environment.NewLine,
(
From
path As String
In
Directory.GetFiles("D:\dir", "*.txt")
Where
IO.Path.GetFileNameWithoutExtension(path) <> "output"
Select
My.Computer.FileSystem.ReadAllText(path, Encoding.UTF8)
)
),
False,
Encoding.UTF8
)
Iterate
If you need to iterate each line and/or each file, store the result in a local variable.
Dim files As IEnumerable(Of String()) = (
From
path As String
In
Directory.GetFiles("D:\dir", "*.txt")
Select
My.Computer.FileSystem.ReadAllText(path, Encoding.UTF8).Split({Environment.NewLine}, StringSplitOptions.RemoveEmptyEntries)
)
For Each file As String() In files
For Each line As String In file
Next
Next
DataSet
If you need to create a DataSet from the result, then take advantage of anonymous types. This way you can store both the name of the file and its lines.
Dim files = (
From
path As String
In
Directory.GetFiles("D:\dir", "*.txt")
Select
New With {
Key .Name = IO.Path.GetFileNameWithoutExtension(path),
.Lines = My.Computer.FileSystem.ReadAllText(path, Encoding.UTF8).Split({Environment.NewLine}, StringSplitOptions.RemoveEmptyEntries)
}
)
Dim data As New DataSet()
With data
.BeginInit()
For Each item In files
With data.Tables.Add(item.Name)
.BeginInit()
.Columns.Add("Column1", GetType(String))
.EndInit()
.BeginLoadData()
For Each line As String In item.Lines
.Rows.Add(line)
Next
.EndLoadData()
End With
Next
.EndInit()
End With

Answer 2

There are few problems in your code:
Your datatable was not initialized
value of w is exceed than the size of files array
Note: I use DataSet to add each DataTable, However you can remove it if it's not required.
Try following code:
Dim fileEntries As String() = Directory.GetFiles("C:\dir\", "*.txt")
' Process the list of .txt files found in the directory. '
Dim filesCount As Integer = Directory.GetFiles("C:\dir\", "*.txt").Count()
Dim ds As New DataSet()
For i As Integer = 0 To filesCount - 1
'do it for every file in folder'
i = i + 1
Dim reader As New System.IO.StreamReader(fileEntries(i))
Dim files As String() = reader.ReadToEnd().Split(New String() {Environment.NewLine}, StringSplitOptions.RemoveEmptyEntries)
Dim lineCount = File.ReadAllLines(fileEntries(i)).Length
Dim w As Integer = 0
Dim dt As New DataTable()
dt.Columns.Add(i.ToString())
'add column "0" for file 1, "1" for file 2 etc.'
While w <> lineCount
If files.Length = w AndAlso w <> 0 Then
Continue While
End If
dt.Rows.Add(files(w))
'write each line in file 1 to column 0, etc.'
w = w + 1
End While
ds.Tables.Add(dt)
Next