I have a CSV file with the following format:
Header 1;Header 2;Header 3;Header 4 1;2;3;4 5;6;7;8 9;10;11;12 13;14;15;16I would like to extract the header and part of the data, for example as follows:
Header 2;Header 3 6;7 10;11MATLAB: How to extract a portion of a CSV file using MATLAB
MATLAB
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Solution One
You do not need to delete the first ten rows from the file, because textscan has an option to ignore header lines, so you can use this instead:
Out = textscan(....,'HeaderLines',10);To read 1280 columns of data you need to define this in the format string, so the final code could be something like this:
fmt = repmat('%f',1,1280);fid = fopen('textfile.txt','rt')out = textscan(fid, fmt, 'Delimiter',',', 'HeaderLines',10);fclose(fid);Solution Two
If the data in the matrix is all numeric (note the header lines do not need to be) then you could use the much simpler dlmread instead, something a bit like this:
out = dlmread('textfile.txt',',',10,0);Examples
% textscan
fmt = repmat('%f',1,5);fid = fopen('temp.txt','rt');out_txt = textscan(fid, fmt, 'Delimiter',',', 'HeaderLines',3);fclose(fid);out_txt = cell2mat(out_txt)% dlmread
out_dlm = dlmread('temp.txt',',',3,0)display this in the command window:
out_txt = 0 1 2 3 4 5 6 7 8 9out_dlm = 0 1 2 3 4 5 6 7 8 9The sample text file that I used is attached here:
Ali - how do you know that your images are in the correct order? For example, what does
Files = dir('*.jpg');return? I'm going to guess that your file names have a number in them, but you may not be getting the order that you expect. For example, the following loop creates a 100 (empty) text files
for k=1:100 fid = fopen(sprintf('test%d.txt',k),'wt'); fclose(fid); endNow when I do
dir('test*.txt')I observe that
test18.txt test28.txt test38.txt test48.txt test58.txt test68.txt test78.txt test88.txt test98.txt test1.txt test19.txt test29.txt test39.txt test49.txt test59.txt test69.txt test79.txt test89.txt test99.txt test10.txt test2.txt test3.txt test4.txt test5.txt test6.txt test7.txt test8.txt test9.txt test100.txt test20.txt test30.txt test40.txt test50.txt test60.txt test70.txt test80.txt test90.txt test11.txt test21.txt test31.txt test41.txt test51.txt test61.txt test71.txt test81.txt test91.txt test12.txt test22.txt test32.txt test42.txt test52.txt test62.txt test72.txt test82.txt test92.txt test13.txt test23.txt test33.txt test43.txt test53.txt test63.txt test73.txt test83.txt test93.txt test14.txt test24.txt test34.txt test44.txt test54.txt test64.txt test74.txt test84.txt test94.txt test15.txt test25.txt test35.txt test45.txt test55.txt test65.txt test75.txt test85.txt test95.txt test16.txt test26.txt test36.txt test46.txt test56.txt test66.txt test76.txt test86.txt test96.txt test17.txt test27.txt test37.txt test47.txt test57.txt test67.txt test77.txt test87.txt test97.txtNote the ordering of the files: 1,10,100,11-19,2,20-29,3,30-39,etc. with early images being inserted every ten images. If your files are named in a similar fashion then you will need to force the correct order or rename he files. If, in the code above, I had named the files as
for k=1:100 fid = fopen(sprintf('test%03d.txt',k),'wt'); fclose(fid); endwhere each integer is padded with up to three zeros, then I get the correct ordering of the files as
dir('test*.txt')test001.txt test012.txt test023.txt test034.txt test045.txt test056.txt test067.txt test078.txt test089.txt test100.txt test002.txt test013.txt test024.txt test035.txt test046.txt test057.txt test068.txt test079.txt test090.txt test003.txt test014.txt test025.txt test036.txt test047.txt test058.txt test069.txt test080.txt test091.txt test004.txt test015.txt test026.txt test037.txt test048.txt test059.txt test070.txt test081.txt test092.txt test005.txt test016.txt test027.txt test038.txt test049.txt test060.txt test071.txt test082.txt test093.txt test006.txt test017.txt test028.txt test039.txt test050.txt test061.txt test072.txt test083.txt test094.txt test007.txt test018.txt test029.txt test040.txt test051.txt test062.txt test073.txt test084.txt test095.txt test008.txt test019.txt test030.txt test041.txt test052.txt test063.txt test074.txt test085.txt test096.txt test009.txt test020.txt test031.txt test042.txt test053.txt test064.txt test075.txt test086.txt test097.txt test010.txt test021.txt test032.txt test043.txt test054.txt test065.txt test076.txt test087.txt test098.txt test011.txt test022.txt test033.txt test044.txt test055.txt test066.txt test077.txt test088.txt test099.txt
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