Sifting through array for matches

Sifting through array for matches

• Yuval124

  If you pass the contents of your arrays to an instance of this class, and then pull them out, there will be no duplicates. If you use this container in general to start with, then you'll get no duplicates right away.

  
  
  

• Rob B

   

  "names are the same, and if they are, then I want to take out one of the matches from that pair"

  I have a favorite old trick for this which relies on a property of dictionaries. They will not allow duplicate keys. Soooooo (critten from memory)

  Dim Dic as new Dictionary (oftype String, integer)

  'Iterating through your list.....

  For i as integer = 0 to list.length-1

  Try

            Dic.add(list(i),i) ' if a dup name is added the dictionary will throw an exception 

           'if needed do non-duplication processing here

  catch

            'if needed do duplication processing here

  end try

  Next

   

   

  
  
  

• ASR

  Unfortunately, I don't believe that VB.NET has a set collection. You can easily create one though:

  Public Class SIList(Of T)

  Inherits System.Collections.Generic.List(Of T)

  Public Overloads Sub Add(ByVal item As T)

  If Not Contains(item) Then

  MyBase.Add(item)

  End If

  End Sub

  End Class

  It's called SIList for SingleInstanceList. Set is taken :-) This will reject any duplicate matches. Using Dictionary to do the same means dealing with exceptions, or writing code to see if the set contains a key, which you may as well do with the List instead. This way, you encapsulate the behaviour you want, which is what OO is all about.

  
  
  

• Breakgate

  In regards to this code:

  Public Class SIList(Of T)

  Inherits System.Collections.Generic.List(Of T)

  Public Overloads Sub Add(ByVal item As T)

  If Not Contains(item) Then

  MyBase.Add(item)

  End If

  End Sub

  End Class
  

  
  I got the code to you know... compile. Just that code alone, but I'm pretty much a clueless nube (for lack of a better term), and I'm not at all sure where to... you know give it my array. So if the array is called personarray... where do i tell it... you know, sift through this buddio
  

  Sorry for being so clueless
  any help is greatly appreciated
  Thanks in advance
  -Robert
  

  
  
  

• arturm

  The code is the same for a Dictionary, Christan. It depends what you are going to do with this 'list': I'm not sure what you mean by dealing with exceptions. Perhaps I'm not understanding what you wrote
  
  

• Jason Holt

  Public Class SIList(Of T)

  Inherits System.Collections.Generic.List(Of T)

  Public Overloads Sub Add(ByVal item As T)

  If Not Contains(item) Then

  MyBase.Add(item)

  End If

  End Sub

  End Class

  If you add this to your project somewhere, then you can create instances of it like this:

  Dim words as SIList(of String) = new SIList(Of String)

  Now you have a container that you can add strings to, but it will only add strings that are not already there. So all you have to do is use this in place of your array, and it will never contain duplicate values. Or, if you have arrays, you can do this

  Dim words as SIList(of String) = new SIList(Of String)

  Dim s as string

  for each s in array1

  words.Add(s)

  next

  for each s in array2

  words.Add(s)

  next

  I believe that words will then have a ToArray() method which will return a new string array, with no duplicate values.

  
  
  

• Fregas

  Hello all,
  Sorry about being consistantly annoying and beginerish. However, I simply cannot figure out what to do with that code that was provided!
  I'm not really a good programmer, nor do I know much... and I'm not really sure how to make the code suggested by Renee sift through an array. I'm sorry for making you spoon feed me, but i'm affraid that's the only way that I'm going to be able to understand this.
  So sorry, any help really is appreciated!
  Thanks so much
  -Robert
  
  
  

• StuartMiller

  If you look at the code Renee wrote, it catches an exception. The Dictionary throws an exception if you insert a duplicate key. My first thought was to offer code like this ( as an exception will slow down the code ), then I thought it better to wrap it, so all the user needs to do is insert items.

  
  
  
• Sifting through array for matches