Tcl/Tk 8.5 Programming Cookbook

Appending list elements

Up to this point, we have manually populated the elements of our list. While this is a usable method for list creation, it will become a necessity to programmatically populate the elements of a list at some point. To accomplish this, Tcl provides the lappend command. The syntax is as follows:

	lappend variable value1 value2 …

How to do it…

In the following example, we will append elements to a list. Return values from the commands are provided for clarity. Enter the following command:

% set input {John Mary Bill}
John Mary Bill

% lappend input Tom
John Mary Bill Tom

How it works…

The lappend command has treated the variable name provided in variable as a list and appended all the following values to variable as list elements. ...