"Dictionary" Objects to Store Keys and Values

VBScript Tutorials - Herong's Tutorial Examples

∟scrrun.dll - Scripting Runtime DLL Library

∟"Dictionary" Objects to Store Keys and Values

This section describes Dictionary object properties and methods. A tutorial example is provided on how to add and remove keys and values into a Dictionary object.

Dictionary: An object representing a collection of pairs of keys and values, working like an associate array in Perl. It offers the following methods and properties:

"Add key, item": Method to add a pair of key and value to this dictionary.
"Exists(key)": Method to return true if the specified key exists in this dictionary.
"Keys()": Method to return an array containing all the keys in this dictionary.
"Items()": Method to return an array containing all the values in this dictionary.
"Remove(key)": Method to remove a pair of key and value from this dictionary.
"RemoveAll()": Method to remove all pairs of keys and values from this dictionary.
"Item(key)": Property to set or return the value associated with the specified key.
"Count": Property to return the number of pairs of keys and values.

Here is a VBScript example to show you how to use "Dictionary" objects:

<html>
<body>
<!-- dictionary_test.html
 - Copyright (c) 2002 HerongYang.com. All Rights Reserved.
-->
<pre>
<script language="vbscript">
   ' Creating a dictionary object
   set user = CreateObject("Scripting.Dictionary")
   ' Adding a pair of key and item
   user.add "FirstName", "Bill"
   user.add "LastName", "Smith"
   user.add "Email", "bill@com.com"
   user.add "Country", "Canada"
   
   ' Iterating through the dictionary
   n = user.Count
   document.writeln("Before - Number of keys: " & n)
   keys = user.Keys()
   for i=0 to n-1
      k = keys(i)
      v = user.Item(k)
      document.writeln(k & ": " & v)
   next
   
   ' Modifying the dictionary
   user.remove("Country")
   user.Item("Email") = "bill@smith.com"
   user.Item("Phone") = "123-456-7890"
   
   ' Iterating through the dictionary
   document.writeln("After - Number of keys: " & n)
   keys = user.Keys()
   for i=0 to n-1
      k = keys(i)
      v = user.Item(k)
      document.writeln(k & ": " & v)
   next
</script>
</pre>
</body>
</html>

Output:

Before - Number of keys: 4
FirstName: Bill
LastName: Smith
Email: bill@com.com
Country: Canada
After - Number of keys: 4
FirstName: Bill
LastName: Smith
Email: bill@smith.com
Phone: 123-456-7890

Note that:

"CreateObject()" method is called to create an empty Dictionary object.
Method with two parameters can not use parentheses to list the parameters, for example, 'user.Add "FirstName", "Bill"'. This is a very strange syntax for experienced programmers, because all most every other language requires parentheses, no matter how many parameters there are in a method call.
Property "Item(key)" can be used on the left hand side of an assignment operator, for example, 'user.Item("Email") = "bill@smith.com"'.
Property "Item(key)" used an assignment statement will force an auto-addition of the specified key to this dictionary, for example, 'user.Item("Phone") = "123-456-7890"'.