asked on

Parse CSV string and perform select & listbox display

Experts,

I have strCardIDs = "1,1,2,2,2,2,3,3,4,1,1,8,8,3,3,3,4,4,4,4,5,6,7,7,7,7,7,7,7,8" (this is retrieved from field in db)
These are the IDs of each of the Cards.

I have table Cards that look like this

ID Title
1 CardOne
2 CardTwo
3 CardThree
4 CardFour
5 CardFive
6 CardSix
7 CardSeven
8 CardEight
etc etc

I have a listbox, lstCards

I want to display the following (the card title, and the quantity of each card as a sum of the number of times it's ID appears in the list. Please note, ID of card could appear anywhere in the string. that is, ID 1 could also appear at the end of the string as well as at the beginning, or in the middle):

Title Quantity
CardOne 4
CardTwo 4
CardThree 5
CardFour 5
CardFive 1
CardSix 1
CardSeven 7
CardEight 3

TIA,

crafuse

x77

You can use a Dictionary(of string,Integer) where Id is strin(key), Count is integer

dim sep As Char() = New Char() {","c}
dim cnt as integer
for each v as string in strCardIDs.split(sep,StringSplitOptions.RemoveEmptyEntries)
if myDict.TryGetValue(v,cnt) then
cnt += 1
myDict(v) = cnt
else
MyDict.Add(v,1)
end if
next

Next enumerate the dictionary (Values, Count) to list values.

x77

On my code I use specific Hash class for many situations as I use it to much (htCnt, HtSuma, HtAvg).
It is very easy built a class that support Hash if it do´nt need remove method.

on htCnt class, I can use:

MyHtCnt.Add(Value) - I do´nt need worry about value already exists ...

At end, I can access the Data Array (note that it is a public) , Sort It ....

Public Class HtCnt(Of T As IComparable(Of T))
    Public Structure Node
        Implements IComparable(Of Node)

        Public Value As T, Cnt As Int32, Nxt As Integer
        Public Overrides Function ToString() As String
            Return Value.ToString & " : " & Cnt.ToString
        End Function

        Public Function CompareTo(ByVal other As Node) As Integer Implements System.IComparable(Of Node).CompareTo
           Return Value.CompareTo(other.value)
        End Function
    End Structure
    Private ReadOnly Indices() As Integer, IndCount As Integer
    Public Data() As Node, Count As Integer
    Public Sub New(ByVal size As Integer)
        If size < 7 Then size = 7
        IndCount = GetPrime(size)
        Indices = New Integer(IndCount - 1) {}
        Data = New Node(size) {}
    End Sub
    '0 - en Array Indices es valor inicial, Entrada vacía
    Public Sub add(ByVal Value As T)
      Dim Index As Int32 = (Value.GetHashCode And &H7FFFFFFF) Mod IndCount
      Dim na As Int32 = Indices(Index) - 1, n = na    'n : Bucket / Node.nxt 
      Do Until n < 0
         With Data(n)
           If Value.Equals(.Value) Then .Cnt += 1 : Return
           n = .Nxt
         End With
      Loop
      If Count >= Data.Length Then Array.Resize(Data, Count << 1)
      Data(Count) = New Node() With {.Value = Value, .Nxt = na, .Cnt = 1} : Count += 1
      Indices(Index) = Count 'Nueva Entrada - Se Encadena al índice
    End Sub

    Public Sub addRange(ByVal Values As IEnumerable(Of T))
      For Each V In Values : add(V) : Next
    End Sub

    Public Function Index(ByVal Value As T) As Int32
      If Value IsNot Nothing Then
          Dim n = Indices((Value.GetHashCode And &H7FFFFFFF) Mod IndCount) - 1
          Do Until n < 0
             With Data(n) : If Value.Equals(.Value) Then Return n Else n = .Nxt
             End With
          Loop
      End If
      Return -1
    End Function
    Public Sub Clear()
        If Count > 1 Then
           Array.Clear(Indices, 0, Indices.Length)
           Array.Clear(Data, 0, Data.Length) : Count = 0
        End If
    End Sub
'  Public Shared Sub TesthtCnt()
'  Dim t = Stopwatch.StartNew
'      Dim h As New HtCnt(Of Integer)(100)
'      For n = 0 To 1000
'          For i = 0 To n
'              h.add(i)
'          Next
'      Next
'Debug.Print(t.Elapsed.ToString)
'      For n = 0 To 1000
'          If h.Index(n) <> n Then Stop
'          If h.Data(n).Cnt <> (1001 - n) Then Stop
'      Next
'  End Sub
End Class


'This method is comon to all my Hash class.
  Private primes() As Integer = {53, 97, 193, 389, 769, 1543, 3079, 6151, 12289, 24593, 49157, 98317, 196613, 393241, 786433, 1572869, 3145739, 6291469, 12582917, 25165843, 50331653, 100663319, 201326611, 402653189, 805306457, 1610612741}

  <DebuggerStepThrough()> _
  Public Function GetPrime(ByVal size As Integer) As Integer
      Dim n As Integer = 0
      If size < 0 Then Throw (New Exception("GetPrime - Size < 0"))
      size >>= 5 : While (size > 0) : size >>= 1 : n += 1 : End While
      Return primes(Math.Min(n, primes.Length - 1))
  End Function

Open in new window

Easwaran Paramasivam

From your string, it contains only the value. The text is missing. However you can keep them in a dictionary/List as well.

List<int,string> objList = new List<int,string>();

objList.Add(1,"CardOne");
objList.Add(2,"CardTwo");
and so on...

string[] keys = strCardIDs.split(",".ToCharArray());
List<int,string> objListRest = new List<int,string>();
int val;
for each (string str in keys )
{
int key = Convert.Toint32(str);

if(objListRest.ContainsKey(key))
{
val = objListRest[key];
val ++;
objListRest[key] = val;
}
else
objListRest[key] = 1;

}

ASKER CERTIFIED SOLUTION

crafuse

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Easwaran Paramasivam

Yes. You can form seperate more select queries with ; seperated. This will execute all the statements. NextResultSet() will give successive result set.

Refer http://csharp.net-informations.com/data-providers/csharp-multiple-resultsets.htm

crafuse

ASKER

EaswaranP:

thanks for that. could you demonstrate using my code? otherwise, i will look into this tomorrow.

Thanks,
crafuse

Shahan Ayyub

Hi!

Please try like this: (see comments also)

Dim MyArray As New ArrayList()
        Dim values() As String = strLibraryList.ToString.Split(",")
        Dim int As Integer = 1
        Dim total As Integer

        MyArray.AddRange(values)
        MyArray.Sort()

        Dim b As Integer
        Dim CardSQL As String
        Dim strCardName As String = String.Empty

        Dim temp As String = String.Empty        'Declaration ends

        For b = 0 To MyArray.Count - 1
            If MyArray(b) <> int AndAlso total > 0 Then
                temp &= MyArray(b) & ","                     ' Concatenate IDs in a variable with comma to use in 'IN clause'
                total = 1
                int = MyArray(b)
            Else
                total += 1
            End If
        Next b

        temp = temp.TrimEnd(",")                       ' Remove ',' at the end of the variable.

        CardSQL = "select name from merchant where cardno IN (" & temp & ")"    ' pass IDs in query ONCE.

        Dim conReader1 As New MySqlConnection(strMySQLConnectString)
        Dim conString1 As New MySqlCommand(CardSQL, conReader1)

        conReader1.Open()   ' Open connection once

        Dim drReader1 As MySqlDataReader
        drReader1 = conString1.ExecuteReader(CommandBehavior.CloseConnection)   ' execute command Once

         'here datareader has all the name you are willing to popup.
         'insert a loop here and read 'drReader1' and display results as you want.


        conReader1.Close()   ' Close connection once.

Open in new window

crafuse

ASKER

Shahan_Developer -

I guess this question was not very clear. Your answer neglects a fundamental aspect of the functionality I'm looking for: that each CardName is listed along with that card's quantity, so that the listbox items look like this:

cardone 10
cardforty 3
cardtwentynine 6
cardsix 1
cardonehundred 9
etcetera x

crafuse

ASKER

will open a new question to help with passing through my db.

Shahan Ayyub

Did you get the logic what I tried to express ?

I don't have further information so i can't test. That was the only reason to add "comments" in my code.

crafuse

ASKER

i suppose i got your logic, yes. what is important, however, is displaying also a count of each cards quantity. populating the listbox with card names derived from a dynamically concatenated string of values is no problem for me, but it's not what i need in this case.

but thank you for your help.

;-)

crafuse

Parse CSV string and perform select &amp; listbox display

Parse CSV string and perform select & listbox display