Search for closest Match

[Domino2006]

Hi guys girls i have a csv file i have read into 3 listboxes all containing 1 row of the 3 columns from the csv. column 1 & 2 contain numbers. i have for example a number 3002.319 and im trying to figure out how to search the columns in listbox 2 for the closest match i.e. 3002.315. my code is as follows.

Dim strfilename As String = "C:\Documents and Settings\crazy\Desktop\data.CSV"



'File to string vars
Dim objSRFile As StreamReader
Dim strInput, arrStrInput() As String
Dim intCurrPos As Integer
Dim sitename, sitepos1, sitepos2 As String


objSRFile = File.OpenText(strfilename)
While objSRFile.Peek <> -1


strInput = objSRFile.ReadLine
arrStrInput = Split(strInput, ",", , CompareMethod.Text)
For intCurrPos = 0 To arrStrInput.Length - 1
Select Case intCurrPos
Case 0
sitename = arrStrInput(intCurrPos)
Case 1
sitepos1 = arrStrInput(intCurrPos)
Case 2
sitepos2 = arrStrInput(intCurrPos)



ListBox1.Items.Add(sitename)
ListBox2.Items.Add(sitepos1)
ListBox3.Items.Add(sitepos2)
End Select
Next

End While

End Sub

 

[cjelec]

I would say that using a DataTable to store the data in and binding the ListBoxes to it would be a better performance option.

If you use a DataTable you can use its functions for searching for rows, which is much faster than going through each item in a ListBox (For ... Next).

You can then use the DataTable.Select function to find the row(s) for you.
First search for an exact match:
Rows = DT.Select("sitepos1 = '" & SomeNum & "'")(0)

Then if none found, search for above:
AboveRows = DT.Select("sitepos1 > '" & SomeNum & "'", "sitepos1")
Or below:
BelowRows = DT.Select("sitepos1 < '" & SomeNum & "'", "sitepos1 DESC")

You could check for the closest row by:
If (AboveRows(0).Item("sitepos1") - SomeNum) > (SomeNum - BelowRows(0).Item("sitepos1")) Then
ClosestRow = BelowRows(0)
Else
ClosestRow = AboveRows(0)
End If