>>>> My problem is that I currently can only plot one spline on the axes. My data will always be over-written the moment I plot another axes. However, when I read from the MATLAB book. It seems that the example are assigning data to structure in a less interactive way with the user. Is there any ways that I can work on the data clicked by the user. Then retrieving the relevant data upon selecting on the spline drawn.

Another problem of mine is that, after I have shifted the original spline to another location. After I apply ‘cla’ function, all the splines have been deleted. Is there any other functions that I can used to delete the original spline after shifting the spline to a new location without deleting other splines on the axes.

Thanks a million,
Magdalene

There are no issues with using dynamic field referencing and the compiler. I don’t see how using feval helps in any way. This method should be robust.

–Loren

Thank you very much.

Pietro Garofalo

Use ‘fieldnames’ to retrieve the names of all fields at one level of the structure. I’ve done something similar to the following a number of times:

fn = fieldnames(mystruct);
for lp=1:length(fn)
doSomeOperation( mystruct.( fn{lp} ) );
end

I’ve become more comfortable just using the field names as the loop arguments outright.

fn = fieldnames(mystruct);
for lp=fn
doSomeOperation( mystruct( lp{:} ) );
end

This works very well for homogenous structures or when your ‘doSomeOperation’ function knows how to handle different input types.
For example, you might define doSomeOperation like this:

function x = doSomeOperation(y)
if ~isnumeric(y)
x = [];
else
x = doSomethingForReal(y);
end

Anyway, it’s a thought.