How I can randomize the content of a text file? - vb.net

Question

I need to randomize ALL the lines inside a text file and then save the unsorted lines by replacing the same text file.
How I can do all that?

Answer 1

Dim filepath as String = "text_path"
Dim arr() As String = File.ReadAlllines(filepath)
Dim a As Random
Dim b(str.Length) As Integer
Dim result=1, c As Integer
File.Delete(filepath)
Dim f As StreamWriter = File.AppendText(filepath)
For i = 0 To str.Length
while(result)
result = 0
c = a.Next(0, str.Length)
For j = 0 To b.Length
If b(j) = c Then result = 1
Next
end while
f.WriteLine(arr(c))
Next
f.Close()

Answer 2

Another take on it:
Imports System.IO
Module Module1
Sub CreateFile(destFile As String)
Using sw = New StreamWriter(destFile)
For i = 1 To 200
sw.WriteLine("Line " & i.ToString)
Next
End Using
End Sub
Function RandomList(nNumbers As Integer) As List(Of Integer)
' generate a List of numbers from 0..nNumbers-1 in a random order.
Dim ns As New List(Of Integer)
Dim rnd As New Random
For i = 0 To nNumbers - 1
ns.Insert(rnd.Next(0, i + 1), i)
Next
Return ns
End Function
Sub RandomiseFile(srcFile As String)
Dim lines = File.ReadAllLines(srcFile)
Dim nLines = lines.Count
Dim randomNumbers = RandomList(nLines)
' use a temporary file in case something goes wrong so that
' the original file is still there.
Dim tmpFile = Path.GetTempFileName()
' output the lines in a random order.
Using sw = New StreamWriter(tmpFile)
For i = 0 To nLines - 1
sw.WriteLine(lines(randomNumbers(i)))
Next
End Using
File.Delete(srcFile)
File.Move(tmpFile, srcFile)
End Sub
Sub Main()
Dim fileToUse As String = "C:\temp\makerandom.txt"
CreateFile(fileToUse)
RandomiseFile(fileToUse)
End Sub
End Module

Answer 3

Here is my take on it:
Dim linesList As New List(Of String)(IO.File.ReadAllLines("filepath"))
Dim newLinesList As New List(Of String)
Randomize()
While linesList.Count > 0
Dim randomIndex As Integer = Math.Floor(Rnd() * linesList.Count)
newLinesList.Add(linesList(randomIndex))
linesList.RemoveAt(randomIndex)
End While
IO.File.WriteAllLines("filepath", newLinesList.ToArray)