Tcl/Tk 8.5 Programming Cookbook

Joining two lists

Now that we have seen how to make a list we will explore combining lists. To accomplish this, Tcl provides the concat command. The syntax is as follows:

	concat value1 value2 …

How to do it…

In the following example, we will concatenate a set of lists containing single characters. Return values from the commands are provided for clarity. Enter the following command:

% concat {a b c} {1 2 3}
a b c 1 2 3

How it works…

The concat command joins each of its arguments together with spaces after first trimming all leading and trailing whitespace, and in the case of a list, the results will be flattened. Although this command will concatenate any arguments provided, we will be focusing on its usage as it applies to the list elements. To ...