How to only have user select data file if workspace is empty?

I have a generic code that calculates things based off of the data file that the user selects and loads into the Matlab Workspace. Here is my code to do that:

%%Load Data
% Open Matlab file (ATI data)
[a,b]=uigetfile('*.mat');
FileATI=fullfile(b,a); 
dataATI = load(FileATI);

I know there is some intrinsic function like "if isempty" that would prevent me from having to select the file every single time I re-run my code. How would I do this? Thanks so much, in advance!

Answer 1

[dpb]

The term "generic" is iffy; but for the case as actually written/posted,

if ~exist('dataATI','var')
 % load file stuff goes here
 ...
end

If any variables different in name are loaded then that's a problem, of course.

[Kelsey]

Thank you so much!!