Matlab skipping subfolders - matlab

Question

I have a folder containing sequential subfolders 000001_wd, 000002_wd,... in which I'm reading data contained in a file called 'plane.txt'. Some of the subfolders don't contain that file. I wish to skip them in a for-if else loop, but it is unable open file.
Tried changing or adding paths but nothing seems to work
workdir = 'D:\wass\test\output_925\';
cd(workdir)
data_frames = [1:1:37];
nframes = numel(data_frames);
V = zeros(nframes,3);
times = zeros(nframes,1);
ii=1;
prev = cd(workdir);
for frame = data_frames
fprintf('Processing frame %d\n',frame);
wdir = sprintf( '%s%06d_wd/', workdir, frame);
cd(wdir)
if exist('plane.txt')
plane_data = importdata([wdir,'plane.txt']);
times(ii) = double(ii-1)/fps;
else
times(ii) = double(ii-1)/fps;
end
ii=ii+1;
end
cd(prev);
fprintf('Saving data...\n');
I want to just continue through the loop until the last subfolder. Is there something I'm missing because the file I'm skipping is in a subfolder of my sequence?

Answer 1

The statement exist('plane.txt') tests to see if the file 'plane.txt' exists in the current directory. If it does, you read a file in the wdir subdirectory. Obviously, you haven't tested if that file exists.
I would simplify your code by reading the data within a try/catch block:
workdir = 'D:\wass\test\output_925\';
data_frames = 1:37; % <- don't use square brackets here, they're useless
nframes = numel(data_frames);
times = zeros(nframes,1);
for ii=1:nframes
frame = data_frames(ii);
fprintf('Processing frame %d\n',frame);
wdir = sprintf( '%s%06d_wd/', workdir, frame);
try
plane_data = importdata([wdir,'plane.txt']);
% do something with plane_data here...
catch
% ignore error
end
times(ii) = double(ii-1)/fps;
end
% ...
Note that I never used cd. You don't need to change directories to read data, and it's always better not to. The importdata statement uses an absolute path, so it does not matter what the current directory is.
A different approach involves getting a list of all files that match 'D:\wass\test\output_925\*\plane.txt':
files = dir(fullfile(workdir, '*', 'plane.txt'));
for ii=1:numel(files)
file = fullfile(files(ii).folder, files(ii).name);
plane_data = importdata(file);
% do something with plane_data here...
end