How to switch cases if certain file is not found in the mentioned directory?

My script run three different conditions at a time. For this it takes three files as input from certain directory. But sometimes there can be one input files or two. So how can I set switch command that will check the directory for first condition and if the files are not found it will move to new conditions.

Here is my dummy code structure,

Condition 01
Experiment_folder = '/home/ali';                     
Exp_uncertainty = dir(fullfile(Experiment_folder,'*experimental_uncertainty_IDT.txt'));
(If not found move to condition 02)
.
.
commands
.
.
end
Condition 02
Experiment_folder = '/home/ali';                     
Exp_uncertainty = dir(fullfile(Experiment_folder,'*experimental_uncertainty_LFS.txt'));
(If not found move to condition 03)
.
.
commands
.
.
end

Condition 03
Experiment_folder = '/home/ali';                     
Exp_uncertainty = dir(fullfile(Experiment_folder,'*experimental_uncertainty_JSR.txt'));
.
.
commands
.
.
end

Answer 1

[Walter Roberson]

dir() will return an empty result if nothing matches; you can test with isempty()

[Mr. 206]

Actually the problem appears in the next line. When there is no such file, dir will return an empty value. And the next commands are, which are not getting any data.

   experimental_uncertainty_IDT = Exp_uncertainty.name;
   uncertainty_file =fullfile(Ignition_Delay_Experiment_folder,experimental_uncertainty_IDT);

As a result this lines are giving error, which I am trying to avoid.

[Walter Roberson]

if ~isempty(Exp_uncertainty)
    ....
end

[Mr. 206]

Thanks, It works.