Max Capacity of IEnumerable(Of String)

Question

Hello,

I use the code below to do some comparison among 2 strings (t1 and t2) :

  Dim ar1 As String() = Split(t1, ",")

  Dim ar2 As String() = Split(t2, ",")

  Dim txtoutput As IEnumerable(Of String) = ar2.Except(ar1)

When I tested the app with t1(almost 1250000 characters) and t2(almost half of the t1 length) , txtoutput returned 0 (but there were actually around 7000 items in common with the input strings).

What's the maximum safe length of input to this method ? What's the maximum count of IEnumerable(Of String) ?

Thanks

P.S project link :

1z3tADujRhUeZ4VXWFNqnNALj5sfGQSL4

My form :

Imports System.ComponentModel
Imports System.Linq
Imports System.Text

Public Class Form1
    Dim t1 As String
    Dim t2 As String
    Dim txtOutput As IEnumerable(Of String)
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim ofd As New OpenFileDialog
        ofd.InitialDirectory = My.Computer.FileSystem.SpecialDirectories.Desktop
        ofd.Filter = "Text|*.txt"

        If ofd.ShowDialog = Windows.Forms.DialogResult.Cancel Then Exit Sub

        Try


            t1 = My.Computer.FileSystem.ReadAllText(ofd.FileName)

            oldLink.Text = Split(t1, ",").Length

            TextBox1.Text = ofd.FileName


        Catch ex As Exception

        End Try
    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        Dim ofd As New OpenFileDialog
        ofd.InitialDirectory = My.Computer.FileSystem.SpecialDirectories.Desktop
        ofd.Filter = "Text|*.txt"

        If ofd.ShowDialog = Windows.Forms.DialogResult.Cancel Then Exit Sub

        Try


            t2 = My.Computer.FileSystem.ReadAllText(ofd.FileName)
            newLink.Text = Split(t2, ",").Length
            TextBox2.Text = ofd.FileName





        Catch ex As Exception

        End Try
    End Sub

    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
        If TextBox1.Text <> "" And TextBox2.Text <> "" And TextBox3.Text <> "" Then
            BackgroundWorker1.RunWorkerAsync()
        End If

    End Sub
    Sub getOutputCount()
        If InvokeRequired Then

            Me.Invoke(New MethodInvoker(AddressOf getOutputCount))
        Else
            finalLink.Text = txtOutput.Count
            Application.DoEvents()
        End If
    End Sub
    Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork

        Dim splt() As Char = {","c}
        Dim ar1 As List(Of String) = t1.Split(splt, StringSplitOptions.RemoveEmptyEntries).ToList
        Dim ar2 As List(Of String) = t2.Split(splt, StringSplitOptions.RemoveEmptyEntries).ToList
        ar1.Sort()
        ar2.Sort()
        txtOutput = ar2.Except(ar1)

        getOutputCount()


        Dim fTx2 As String = String.Join(",", txtOutput)




        My.Computer.FileSystem.WriteAllText(TextBox3.Text, fTx2, True)


    End Sub

    Private Sub BackgroundWorker1_ProgressChanged(sender As Object, e As ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
        ProgressBar1.Value = e.ProgressPercentage

    End Sub

    Private Sub BackgroundWorker1_RunWorkerCompleted(sender As Object, e As RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
        MsgBox("Done!")
        Button3.Enabled = False
    End Sub

    Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
        Dim ofd As New SaveFileDialog
        ofd.InitialDirectory = My.Computer.FileSystem.SpecialDirectories.Desktop
        ofd.Filter = "Text|*.txt"

        If ofd.ShowDialog = Windows.Forms.DialogResult.Cancel Then Exit Sub

        Try


            TextBox3.Text = ofd.FileName





        Catch ex As Exception

        End Try
    End Sub

End Class

Answer 1

Using the published files, the next sample program:

Dim t1 = File.ReadAllText("T1.txt")
Dim t2 = File.ReadAllText("T2.txt")
Dim ar1 = t1.Split(","c)
Dim ar2 = t2.Split(","c)
Dim result1 = ar2.Except(ar1)
Dim result2 = ar1.Except(ar2)
Dim result3 = ar1.Intersect(ar2)

Console.WriteLine(ar1.Length)
Console.WriteLine(ar1.Distinct().Count())
Console.WriteLine(ar2.Length)
Console.WriteLine(ar2.Distinct().Count())
Console.WriteLine(result1.Count())
Console.WriteLine(result2.Count())
Console.WriteLine(result3.Count())

gives these results:

• 1332 items in ar1, no duplicates
• 7066 items in ar2, 4548 unique items after removing duplicates
• 3216 items in ar2 excepting items from ar1
• 0 items in ar1 excepting items from ar2
• 1332 common items in ar1 and ar2

Maybe the confusion is caused by duplicates.

Answer 2

Try it like this

        Dim splt() As Char = {","c}
        Dim ar1 As List(Of String) = t1.Split(splt, StringSplitOptions.RemoveEmptyEntries).ToList
        Dim ar2 As List(Of String) = t2.Split(splt, StringSplitOptions.RemoveEmptyEntries).ToList
        ar1.Sort()
        ar2.Sort()
        Dim txtoutput As IEnumerable(Of String) = ar2.Except(ar1)