Matlab set() figure title raises exception

Question

I'm writing a function which ought to plot to an already created axes. The function provides the option to re-title the axes, and I'm trying to make that functionality work.

If the axes doesn't already have a title then just calling title() works, of course.

But: If the axes does already have a title, then calling title() overprints the original title, but leaves the original in place.

So: I've been experimenting with set():

T_old = get(gca, 'Title');
T_new = set(T_old, 'String', 'New Title');

Which leaves me the error message:

One or more output arguments not assigned during call to "set".

What am I doing wrong? Are there other arguments which must be set for the Title handle? And if so what?

Answer 1

Set does not have any output arguments, thus call set(T_old, 'String', 'New Title'); without any return variables.

Answer 2

From the help for set:

A = set(H, 'PropertyName')
set(H,'PropertyName')
returns or displays the possible values for the specified property of the object with handle H. The returned array is a cell array of possible value strings or an empty cell array if the property does not have a finite set of possible string values.

However, you're calling set and and actually setting a property value. This is not a valid input pattern. Just call this instead:

set(T_old, 'String', 'New Title');