Tcl/Tk 8.5 Programming Cookbook

Determining the number of elements

To provide more flexibility to our programs, it will be necessary to create and maintain your lists dynamically. As this will result in a list of indeterminate size, we need a means to determine the number of elements in a list. To accomplish this, Tcl provides the llength command. The syntax is as follows:

	llength list

How to do it…

In the following example, we will pass a list to the llength command to determine the number of elements the list contains. Return values from the commands are provided for clarity. Enter the following command:

% llength {John Mary { Bill Tom }}
3

How it works…

The llength command accepts a list (in this case, a list containing an embedded list with multiple elements) as an argument ...