Vectorize strcat and str2num for loop

Question

Jed Abanat 2019-3-27

0
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https://ww2.mathworks.cn/matlabcentral/answers/452652-vectorize-strcat-and-str2num-for-loop

评论： madhan ravi 2019-3-27

I'm trying to speed up this for loop function. Basically want to to concatonate two integrers, but as the columns and frames variables contain different number of significant figures, I need to include leading zeros. I have tried using a decimal place to merge the values, but the rounding fails for large column/frame numbers. Is there any way I can speed up this for loop, or other efficient ways to do this?

nframes = 1800;
ncols = 801;
columns = 1:ncols;
frames = 1:nframes;
frames = repmat(frames,ncols,1);
columns = repmat(columns,1,nframes);
frames = frames(:);
columns = columns(:);
ID = zeros(1,nframes*ncols);
tic
for xx = 1:nframes*ncols
ID(xx) = str2num(strcat(sprintf('%03i',columns(xx)),sprintf('%04i',frames(xx))));
end
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