CODEWITHSUNDEEP
vb.net
Kane31
Kane31

Reputation: 13

How to load a .txt file and erase after delimiter on each line

I am loading a .txt file that contains around a thousand names in a firstName:lastName format. I only need the firstnames for what I'm doing right now. How can I strip the entire list, which is displayed in a listbox, and display first names only?

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    OpenFileDialog1.Title = "Please Select a File"
    OpenFileDialog1.InitialDirectory = "C:temp"
    OpenFileDialog1.ShowDialog()
End Sub

Private Sub OpenFileDialog1_FileOk(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles OpenFileDialog1.FileOk
    Dim strm As System.IO.Stream
    strm = OpenFileDialog1.OpenFile()
    TextBox2.Text = OpenFileDialog1.FileName.ToString()
    ListBox1.Items.AddRange(System.IO.File.ReadAllLines(TextBox2.Text))
End Sub

Upvotes: 1

Views: 45

Answers (2)

Mark
Mark

Reputation: 8160

Use String.Split to break each line apart at the delimiter and use the first part returned:

ListBox1.Items.AddRange(
    System.IO.File.ReadLines(TextBox2.Text).Select(
        Function(x) x.Split(":"c)(0)
    ).ToArray()
)

I used ReadLines instead of ReadAllLines, since it may be a little more efficient, but it looks like AddRange needs an array anyway, hence the ToArray call.

However, it really depends on what you are going to do once you have the items in the list. It may be better to create a class for the full names and read the file into a list of those, and then bind using DataSource and DisplayMember.

Upvotes: 1

djv
djv

Reputation: 15774

You can split each line into a sub-array, and return the first element into a new array

Private Sub OpenFileDialog1_FileOk(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles OpenFileDialog1.FileOk
    Dim strm As System.IO.Stream
    strm = OpenFileDialog1.OpenFile()
    TextBox2.Text = OpenFileDialog1.FileName.ToString()
    ListBox1.Items.AddRange(
        System.IO.File.ReadAllLines(TextBox2.Text).
        Select(Function(l) l.Split(":"c).FirstOrDefault()).
        ToArray())
End Sub

Upvotes: 1

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