Visual Basic/Collections

      Collection class provides an array-like container more flexible than an array in some ways and less flexible in other ways. More flexible in some ways than Collection is Dictionary class.

      Creating a new collection:

        Dim Cats As Collection
  Set Cats = New Collection

      Iterating over a collection:

        For Each Cat In Cats
     Rem Do something on Cat
  Next

      Adding an item:

         Cats.Add "Item"
   Cats.Add "Item", "Key"
   ...

      Accessing an item at an index, in a read-only way:

        Cats (3) 'The third member of the collection
  Cats.Item(3) 'An alternative
  Cats.Item("Key 3") 'Works if an item has a key associated

      Overwriting a item at an index:

      There is no straightforward way.

      Removing an item:

        Collection.Remove Index
  Collection.Remove HashKey

      The size of a collection:

        Cats.Count

      Testing the emptiness of a collection:

        If Cats.Count=0 Then
    '...
  End If

      Testing the presence of an element in a collection:

        MatchFound = False
  For Each Member In MyCollection
    If Member = "SoughtValue" Then
      MatchFound = True
      Exit For
    End If
  Next

      Appending one collection to another:

        For Each Member In AppendedCollection
    ExtendedCollection.Add Member
  Next

      Converting a collection to an array:

        Dim MyArray
  ReDim MyArray(MyCollection.Count - 1)
  Index = 0
  For Each Member In MyCollection
    MyArray(Index) = Member
    Index = Index + 1
  Next
      Last modified on 9 September 2012, at 18:23