variable format issue using copyfile

Hello Matlab community!

I am having what is probably a really simple issue using copyfile that I can't seem to debugg so hoping someone can help.

I am simply trying to copy an image file from one folder to another using specific paths. The code is here:

finalImgStr = (['RUN0',sprintf('%d',i), '_plot_0020.jpg']);
            outputDir = ([projfilepath, '\Output\Run', sprintf('%d',i)]);
            finalImg = fullfile(outputDir, finalImgStr); 
            
            finalImg1 = convertCharsToStrings(finalImg);
            destDir1 = convertCharsToStrings(destDir);
            
            copyfile ('finalImg1', 'destDir1');
            
            

When I try and run it I get an error saying 'no matching files were found'. However I have checked all the variables and the file paths are correct, and the image is in the source directory etc.

The variables were initially character arrays hence I have converted them to string array's (although the error is the same even if I leave them as characters...)

I'm assuming it's something to do with the formatting/data types but I can't work it out so any help would be appreciated!

Answer 1

[Stephen23]

Your main bug is on this line:

copyfile('finalImg1', 'destDir1');

Your code looks for files literally called 'finalImg1', which is unlikely to be what you want.

You need to refer to the variables, and not use literal strings/character vectors:

copyfile(finalImg1, destDir1);

Some other improvements:

1. use fullfile rather than concatenating paths.
2. use sprintf with the complete name, rather than just the numeric part.
3. pointless data-type conversion is... errr, pointless. Don't.

For example, something like this:

fnm = sprintf('RUN0%d_plot_0020.jpg',i);
sub = sprintf('Run%d',i);
old = fullfile(projfilepath,'Output',sub,fnm);
copyfile(old,destDir1);

Note that your leading zero is rather suspicous, I suspect that you actually want a leading zero but only for one digit (and not for two or more) in which case sprintf can handle this:

fnm = sprintf('RUN%02d_plot_0020.jpg',i);

[dweather]

Thanks for this, especially the extra bits! I knew it was something as simple as that.

Much appreciated :)

[Michelle De Luna]

@Stephen: Hi Stephen! I had a quick question that appears to be similar to the one you helped resolve here, so I thought I might try my luck to see if you see this message. I have an 800x1 char array ("relevant_files") with the name of .nc4 files that I would like to select from an existing folder and move to a new folder ("myFolder"). However, when I try to use the "relevant_files" variable with the copyfile function, I get an error message. I assume the issue is that I cannot read a variable using the function (I must explicitly write the name of the individual files I am looking for), but I was wondering if you had any tips I might be able to use. Any help would be greatly appreciated. Here's what I have so far:

relevant_files = [];
for i = 1:length(x)
    year = num2str(x(i,1));
    month = num2str(x(i,2), '%02.f');
    day = num2str(x(i,3), '%02.f');
    file_name = strcat('north_winds_Np.',year,month,day,'.nc4.nc4');
    relevant_files = [relevant_files; file_name];
end
relevant_files

mkdir myFolder
movefile relevant_files myFolder

[Stephen23]

The first bug is on these lines:

mkdir myFolder
movefile relevant_files myFolder

where you use command syntax instead of the required function syntax:

https://www.mathworks.com/help/matlab/matlab_prog/command-vs-function-syntax.html

The second bug is that because you are trying to move multiple files using by their individual names (i.e. as opposed to use a wildcard character) you will have to loop over the names and call MOVEFILE for each one.

Note that those date strings are probably easier to generate using COMPOSE:

x = [1990,12,31;1984,2,29;1900,1,1]

x = 3×3

1990 12 31 1984 2 29 1900 1 1

compose('%04d%02d%02d',x)

ans = 3×1 cell array
    {'19901231'}
    {'19840229'}
    {'19000101'}

Although, given that you will need a loop anyway (for MOVEFILE), you can simply call SPRINTF for each name inside the loop.