how to get first line and last line of selecteditem from txt file

Question

i try this code for the first line and last line but for all the txt file data

 Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click

        'this code to get the first and last line for all txt file
        Dim fl() As String '(First line)
        Dim ll() As String '(last line)

        fl = File.ReadAllLines("c:\test.txt")
        ll = File.ReadAllLines("c:\test.txt")

        For I As Integer = 0 To LBound(fl) + 1
            TextBox1.Text = (fl(I))
        Next
        For I As Integer = 0 To UBound(ll)
            TextBox2.Text = (ll(I))
        Next

    End Sub

this the example file pic

i used this code to get first line and last line of group as (si) that  populated in combobox called Comcompanyname3

 'this code to write the list line of the group

        Dim Lines As String()
        Lines = File.ReadAllLines("c:\test.txt")


        For Each line In Lines
            If line.Contains(Comcompanyname3.SelectedItem.ToString()) Then
                TextBox1.Text = line
            End If
        Next

but i got the last line of group si

1-how to get the first line

2-how to get the count of the group lines like si = 4

thank you for your help

Answer 1

Here is an example

        Dim Lines As String()
        Lines = File.ReadAllLines("c:\test.txt")
        Dim LineList As New List(Of String)

        For Each line In Lines
            If line.Contains(Comcompanyname3.SelectedItem.ToString()) Then
                'Put all the lines that contains "SI" in a list
                LineList.add(line)
            End If
        Next
        'Put the first one in a text box
        TextBox1.Text = LineList(0)

        'Put the last one in a text box
        TextBox2.Text = LineList(LineList.Count - 1)

        'Get the number of line that contains "SI"
        Dim NB As Integer = LineList.Count

Answer 2

using Crazypennie's code + LINQ:

'Put the first one in a text box
TextBox1.Text = LineList.First

'Put the last one in a text box
TextBox2.Text = LineList.Last

---

thanks for any help

Answer 3

thank you for your great help

Answer 4

thank you for your help

Answer 5

hi

I do not if you allow me to ask again for the same code or i have to ask new question?

How to get the max value of column by the group

i used the code above and i add some code but i got error

this the code

 Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click


        Dim fe As String()
        fe = IO.File.ReadAllLines("c:\test.txt")
        Dim LineList As New List(Of String)
        
        For Each line In fe
            If line.Contains(Comcompanyname3.SelectedItem.ToString()) Then
                'Put all the lines that contains "SI" in a list
                LineList.Add(line)
            End If
        Next
        ''Put the first one in a text box
        TextBox1.Text = LineList(0)
        'TextBox1.Text = LineList.First '(2 way to get first line using LINQ)

        
        ''Put the last one in a text box
        TextBox2.Text = LineList(LineList.Count - 1)
        'TextBox2.Text = LineList.Last '(2 way to get last line using LINQ)

        'Get the number of line that contains "SI"
        Dim NB As Integer = LineList.Count
        TextBox4.Text = NB


        Dim arrayForTheLine = Lines.Split(","c)
        'will convert the following formats date (yyyymmdd),(yyyy/mm/dd),(yyyy-mm-dd) ToShortDateString 
        Dim strDate = If(Date.TryParse(arrayForTheLine(1), Nothing), _
        CDate(arrayForTheLine(1)), CDate(New Date(Val(arrayForTheLine(1).Substring(0, 4)), Val(arrayForTheLine(1).Substring(4, 2)), Val(arrayForTheLine(1).Substring(6, 2))).ToShortDateString))
        Dim strO = arrayForTheLine(2)
        Dim strH = arrayForTheLine(3)
        Dim strL = arrayForTheLine(4)
        Dim strCl = arrayForTheLine(5)
        Dim strV = arrayForTheLine(6)
        TextBox5.Text = maxScore.Date
        TextBox6.Text = maxScore.strh
        TextBox7.Text = maxScore.strl
        TextBox8.Text = maxScore.strcl
        TextBox9.Text = maxScore.strv


    End Sub

and i am trying to get the max vale for given lines

like gd  how to get the the max value of the first 4 lines of the <o>  column ?

also i try this code but still not working

Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click


        Dim fe As String()
        fe = IO.File.ReadAllLines("c:\test.txt")
        Dim LineList As New List(Of String)
        
        For Each line In fe
            If line.Contains(Comcompanyname3.SelectedItem.ToString()) Then
                'Put all the lines that contains "SI" in a list
                LineList.Add(line)
            End If
        Next
        ''Put the first one in a text box
        TextBox1.Text = LineList(0)
        'TextBox1.Text = LineList.First '(2 way to get first line using LINQ)

        
        ''Put the last one in a text box
        TextBox2.Text = LineList(LineList.Count - 1)
        'TextBox2.Text = LineList.Last '(2 way to get last line using LINQ)

        'Get the number of line that contains "SI"
        Dim NB As Integer = LineList.Count
        TextBox4.Text = NB


        Dim arrayForTheLine = Lines.Split(","c)
        'will convert the following formats date (yyyymmdd),(yyyy/mm/dd),(yyyy-mm-dd) ToShortDateString 
        Dim strDate = If(Date.TryParse(arrayForTheLine(1), Nothing), _
        CDate(arrayForTheLine(1)), CDate(New Date(Val(arrayForTheLine(1).Substring(0, 4)), Val(arrayForTheLine(1).Substring(4, 2)), Val(arrayForTheLine(1).Substring(6, 2))).ToShortDateString))
        Dim strO = arrayForTheLine(2)
        Dim strH = arrayForTheLine(3)
        Dim strL = arrayForTheLine(4)
        Dim strCl = arrayForTheLine(5)
        Dim strV = arrayForTheLine(6)
        Dim columnQuery = From line1 In Lines
                               Let x = line1.Split(",")
                               Where x(2) < "<o>"
                               Select Convert.ToDouble(x(2))

        ' Execute and cache the results for performance.
        ' Only needed with very large files.
        Dim results = columnQuery.ToList()


        ' Perform aggregate calculations 
        ' on the column specified by col.
        Dim avgScore = Aggregate score In results Into Average(score)
        Dim minScore = Aggregate score In results Into Min(score)
        Dim maxScore = Aggregate score In results Into Max(score)
        TextBox5.Text = maxScore
        TextBox6.Text = minScore
        TextBox7.Text = avgScore

    End Sub

thank you for your help

Answer 6

hi

i use this code 

Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click


        Dim Lines As String()
        Lines = File.ReadAllLines("c:\test.txt")
        Dim LineList As New List(Of String)

        For Each line In Lines
            If line.Contains(Comcompanyname3.SelectedItem.ToString()) Then
                'Put all the lines that contains "SI" in a list
                LineList.Add(line)
            End If

        Next

        ''Put the first one in a text box
        TextBox1.Text = LineList(0)
        'TextBox1.Text = LineList.First '(2 way to get first line using LINQ)


        ''Put the last one in a text box
        TextBox2.Text = LineList(LineList.Count - 1)
        'TextBox2.Text = LineList.Last '(2 way to get last line using LINQ)


        'Get the number of line that contains "SI"
        Dim NB As Integer = LineList.Count
        TextBox5.Text = NB
        


        For Each line In Lines
            If line.Contains(Comcompanyname3.SelectedItem.ToString()) Then
                'Put all the lines that contains "SI" in a list
                Dim arrayForTheLine = line.Split(","c)
                Dim strO = arrayForTheLine(2)
                Dim strH = arrayForTheLine(3)
                Dim strL = arrayForTheLine(4)
                Dim strCl = arrayForTheLine(5)
                Dim strV = arrayForTheLine(6)
            End If

        Next
        Dim columnQuery = From line1 In Lines
                               Let x = line1.Split(",")
                               Where x(2) < "<o>"
                               Select Convert.ToDouble(x(2))

        ' Execute and cache the results for performance.
        ' Only needed with very large files.

        Dim results = columnQuery.ToList()


        ' Perform aggregate calculations 
        ' on the column specified by col.
        Dim avgScore = Aggregate score In results Into Average(score)
        Dim minScore = Aggregate score In results Into Min(score)
        Dim maxScore = Aggregate score In results Into Max(score)
        TextBox4.Text = maxScore
        TextBox6.Text = minScore
        TextBox7.Text = avgScore

    End Sub

but it  is return the results for the all txt file not by group as si or fa ....ETC

thank you for your help