Tcl/Tk 8.5 Programming Cookbook

Joining list elements

While the concat command is more than capable of merging lists and arguments into a single list, Tcl also provides the join command to expand the functionality. The join command will not only merge the arguments, but also allows insertion of a separation character into the returned string. Note that the variable provided must contain a list, set of lists, or standalone values. The syntax is as follows:

	join list delimiter

How to do it…

In the following example, we will join the elements of a list and create a comma-delimited string. Return values from the commands are provided for clarity. Enter the following command:

% set input {John Mary Bill}
John Mary Bill

% join $input ", "
John, Mary, Bill

How it works…

The join command ...