CODEWITHSUNDEEP
arraysvb.net
Calum
Calum

Reputation: 3

Find index of multiple strings in a multidimensional array

I have a 2 dimensional array that contains multiple strings. It looks something like this;

[1] [2] [3]  
[1] [4] [5]  
[7] [9] [8]

I need a piece of code that returns the index of all positions [1] occurs within the array.

Upvotes: 0

Views: 6069

Answers (3)

petrosmm
petrosmm

Reputation: 550

This an improved answer of tinstaafl's code

Sub CountryCode(ByVal searchterm As String)
    Dim data As New List(Of List(Of String))(
        {
            {"AF", "Afghanistan"}.ToList,
            {"AL", "Albania"}.ToList,
            {"DZ", "Algeria"}.ToList,
            {"AS", "American Samoa"}.ToList,
            {"AD", "Andorra"}.ToList,
            {"AO", "Angola"}.ToList,
            {"AI", "Anguilla"}.ToList,
            {"AQ", "Antarctica"}.ToList,
            {"AG", "Antigua And Barbuda"}.ToList,
            {"AR", "Argentina"}.ToList,
            {"AM", "Armenia"}.ToList,
            {"AW", "Aruba"}.ToList,
            {"AU", "Australia"}.ToList,
            {"AT", "Austria"}.ToList,
            {"AZ", "Azerbaijan"}.ToList
        })

    Dim coords As New List(Of Tuple(Of Integer, Integer))
    For Row As Integer = 0 To data.Count - 1
        Dim found As Integer = data(Row).IndexOf(searchterm)
        If found >= 0 Then
            Debug.Print(Row, found)
            coords.Add(New Tuple(Of Integer, Integer)(Row, found))
            'Based on the index number of the item and the second piece will be displayed
            '{"AF", "Afghanistan"}.ToList,      'index: 1       "AF" is item 1 and "Afghanistan" is item 2
            '{"AL", "Albania"}.ToList,          'index: 2       "AL" is item 1 and "Albania" is item 2
            '{"DZ", "Algeria"}.ToList,          'index: 3       
            '{"AS", "American Samoa"}.ToList,   'index: 4
            '{"AD", "Andorra"}.ToList,          'index: 5
            Debug.Print(data(Row).Item(1).ToString) 'prints anything in the right column... searchterm = "AT" would print "Austria"
        End If
    Next
End Sub

Upvotes: 1

tinstaafl
tinstaafl

Reputation: 6948

If your data contains a lot of elements you might not want to iterate through every element. Using a List(Of List(Of String)) would allow you to only loop through the outer list and just check the inner lists. something like this:+

    Dim data As New List(Of List(Of String))(
        {
            {"[1]", "[2]", "[3]"}.ToList,
            {"[1]", "[4]", "[5]"}.ToList,
            {"[7]", "[9]", "[8]"}.ToList
        })
    Dim searchterm As String = "[1]"
    Dim coords As New List(Of Tuple(Of Integer, Integer))
    For Row As Integer = 0 To data.Count - 1
        Dim found As Integer = data(Row).IndexOf(searchterm)
        If found >= 0 Then
            coords.Add(New Tuple(Of Integer, Integer)(Row, found))
        End If
    Next

Upvotes: 0

Victor Zakharov
Victor Zakharov

Reputation: 26424

Here is a code sample for you:

Dim a(,) As String = {{"[1]", "[2]", "[3]"},
                      {"[1]", "[4]", "[5]"},
                      {"[7]", "[9]", "[8]"}}

Dim indexList As New List(Of Tuple(Of Integer, Integer))
For iRow As Integer = 0 To UBound(a, 1)
  For jCol As Integer = 0 To UBound(a, 2)
    If a(iRow, jCol) = "[1]" Then 'save i and j somewhere
      indexList.Add(New Tuple(Of Integer, Integer)(iRow, jCol))
    End If
  Next
Next

At the end of execution, indexList has two values, (0,0) and (1,0), where the first index is a row, and the second is a column. You may want to change this to use your custom structure instead of a Tuple. Generics are kind of hard to debug in the long run, because of weird names showing up in debugger.

Upvotes: 0

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