Image File Reading, Error with Strings...?

I am trying to read an image file (in the same matlab folder as the code).

Right now, my code is:

shapes = {'Tri', 'Rec', 'Cir', 'Oct'};
num = 1:20;

file = strcat(shapes(i), num2str(num(k)), '.png');
I = imread(file);

However, I am getting an error that the file name has to be a string. I also tried making an array like this:

nums = {'1', '2', '3', '4', '5', '6', '7', '8', '9', '10', '11', '12', '13', '14', '15', '16', '17', '18', '19', '20'};

And instead used

file = strcat(shapes(i), nums(k), '.png');

But still I got the same error.

If anyone can help with this problem it would be great. ^^

P.S. Is there an easy way to import a file that is in a folder that is inside the Current Folder? Thanks.

Answer 1

[Image Analyst]

Try this:

shapes = {'Tri', 'Rec', 'Cir', 'Oct'};
num = 1:20;

% Loop over every shape and every number in "num"
for i = 1 : length(shapes)
  for k = 1 : length(num)
    thisNumber = num(k); % Extract the number.
    % Construct the full file name.
    thisFileName = sprintf('%s%d.png', shapes{i}, thisNumber);
    fullFileName = fullfile(pwd, thisFileName);
    fprintf('Looking for %s\n', fullFileName);
    % Check if the file exists.
    if exist(fullFileName, 'file')
      fprintf('    Found %s\n', thisFileName);
      thisImage = imread(file);
      % Now do something with thisImage.
    else
      fprintf('    Did not find %s\n', thisFileName);
    end
  end
end