Indexing

The Idea of Indexing

• Indexing means having several data items organized under a single name where the individual items can be referred to by number

• It’s like having an address where you need a house number as well as a street name

• Indexing is extremely useful for cycling through a group of items using a loop

• We’ve already seen this used in strings

String Structure

• A string in VBA can be variable length and has an internal structure

• Each character in the string has a position number, called an index

• The first character has index 1, etc. So the string “This is a string.” has 17 characters, counting the blanks:

T h i s i s a s t r i n g .1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Indexing in Listboxes

• We’ve been using listboxes as a place to print information on a user form

• But they can also be used in a much more flexible way to store and access information

• The workbook called IndexListBox has examples of how to use these features

• One important fact: indexing in a listbox starts at 0 instead of 1

Some Useful Properties

• lstName.Listcount is the number of items in list box lstName

• lstName(anIndex) is the item in the listbox lstName with index anIndex

• lstName.ListIndex is the index of the selected item in the listbox

Demo: Index ListBox