Visual Basic/Dictionaries

Dictionary class provides some functions beyond those provided by Collection class. A dictionary is a list of key, value pairs. Unlike Collection, Dictionary class is only available via Microsoft Scripting Runtime, a reference to which needs to be added to your project in order to use the class. Creating a dictionary: Set Dict = New Dictionary Set Dict = CreateObject("Scripting.Dictionary") 'An alternative Adding a key and an item to a dictionary: Dict.Add "Key1", "Value1" Dict.Add "Key2", "Value2" Dict.Add Key:="Key3", Item:="Value3" Accessing an item by key: Value3 = MyDict.Item("Key3") Accessing an item by index: Index = 2 Counter = 1 For Each Key In Dict.Keys If Counter = Index Then FoundKey = Key FoundValue = Dict.Item(Key) Exit For End If Counter = Counter + 1 Next Iterating through the keys: For Each Key In Dict.Keys Value = Dict.Item(Key) Next Iterating through the values: For Each Value In Dict.Items '... Next Removing an item: Dict.Remove "Key3" Removing all items or emptying: Dict.RemoveAll Size or number of elements: Dict.Count Testing for emptiness: If Dict.Count = 0 Then '... End If Changing the key of an item: Dict.Key("Key1") = "Key1a" Changing the value of an item: Dict.Item("Key2") = "Value2a" Testing for presence of a key: If Dict.Exists("Key2") Then '.. End If Using dictionary as a set: Associate the dummy value 1 with each element of the set. When adding an item, test for existence. Set DictSet = New Dictionary DictSet.Add "Item1", 1 'DictSet.Add "Item1", 1 -- error: the item is already there If Not DictSet.Exists("Item1") Then DictSet.Add "Item1", 1 End If DictSet.Remove "Item1"