Image read series does not exist for & if

Hello,

I have images in a folder. They are named "1.jpg","2.jpg" etc. But lets say I want to read from 1-4 but "3.jpg" does not exist. I want the program to skip and read "4.jpg". Basically in my sample code I want to replace the statement "Does not exist" but something that recognizes that "3.jpg" does not exist and moves onto "4.jpg"

for n = 1:4 %All images in folder read, but e.g. 3 does not exist
     A = ['' num2str(n,'%01d') '.jpg'] 
  if A= "Does not exist" %Need to replace this line by something that recognizes that certain image is missing
  A = ['' num2str(n+1,'%01d') '.jpg'] 
  else
      A = imread(A);
   end
end

Answer 1

[Image Analyst]

for n = 1 : 4
  filename = sprintf('%01d.jpg', n);
  if exist(filename, 'file')
    theImage = imread(filename);
  end
end

Alternatively:

for n = 1 : 4
  filename = sprintf('%01d.jpg', n);
  if ~exist(filename, 'file')
      continue; % Skip to bottom of loop.
  end
  theImage = imread(filename);
end

For better, more robust coding, see the FAQ: http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

[Minhal]

Thank you for the quick and precise reply.

Answer 2

[the cyclist]

You could use the dir() function to find the names of all the jpg files in the directory, and then use the ismember() command to check if each one is there.

% Get the jpg files
fileStruct = dir('*.jpg');

% Convert to a cell for convenience
fileCell = struct2cell(fileStruct);

% First row of the cell array has the filenames
if ismember('1.jpg',fileCell(1,:))
    disp('is there')
else
    disp('is not')
end

If can specify the exact pattern of files you want to process inside the dir() command, then you could also just use that list in a for loop directly, without needing to check individual files.