MATLAB Answers

Matthew
0

Loop to read in CSV Values by incrementing a part of the Filename

Asked by Matthew
on 9 Nov 2012
Hello,
I have need to read in several hundred .CSV files using xlsread. The filenames are the same, except for one number at the end.
The files are all kept in the same folder.
I am currently using:
BAM_186_Torque_8Nov_Values = [ xlsread('8NOV12 -- 0656.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0657.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0658.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0659.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0700.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0701.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0702.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0703.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0704.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0705.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0706.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0707.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0708.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0709.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0711.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0712.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0713.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0714.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0715.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0716.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0717.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0718.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0719.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0720.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0721.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0722.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0723.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0724.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0725.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0726.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0727.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0728.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0729.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0730.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0731.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0732.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0733.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0734.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0735.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0736.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0737.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0738.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0739.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0740.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0741.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0742.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0743.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0744.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0745.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0746.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0747.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0748.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0749.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0750.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0751.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0752.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0753.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0754.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0755.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0756.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0757.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0758.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0759.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0800.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0801.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0802.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0803.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0804.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0805.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0806.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0807.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0808.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0809.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0810.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0811.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0812.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0813.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0814.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0815.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0816.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0817.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0818.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0819.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0820.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0821.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0822.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0823.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0824.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0825.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0826.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0827.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0828.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0829.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0830.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0831.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0832.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0833.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0834.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0835.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0836.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0837.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0838.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0839.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0840.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0841.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0842.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0843.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0844.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0845.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0846.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0847.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0848.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0849.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0850.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0851.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0852.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0853.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0854.CSV',1,'G15:G1014')'; xlsread('8NOV12 -- 0855.CSV',1,'G15:G1014')';
xlsread('8NOV12 -- 0856.CSV',1,'G15:G1014')';
];
Is there a way to make a loop to do this for me?
Thank you!

  1 Comment

This is covered by the FAQ: http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F Just minor modifications to the demo code there and you'll be on your way.

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1 Answer

Answer by Dr. Seis
on 9 Nov 2012
Edited by Dr. Seis
on 9 Nov 2012
 Accepted Answer

Should be able to do that:
M = 201; % Number of CSV files
N = 1000; % Number of datapoints in each CSV
BAM_186_Torque_8Nov_Values = zeros(M,N); % Intialize output dataset
for ii = 1 : M
filename = sprintf('8NOV12 -- 0%d.CSV',655+ii); % Create string for each file
tempdata = xlsread(filename,1,'G15:G1014')'; % Grab data from file
BAM_186_Torque_8Nov_Values(ii,:) = tempdata; % Put into output dataset
end

  3 Comments

You will have to get creative if you have numbers that are greater than 999 and less than 100 (i.e., you will need to set up your file naming line for conditions other than 3-digit numbers if you "pad" those numbers with 0's in your filenames).
And you can actually skip the "tempdata" line... you don't really need an intermediate step, I just thought it might describe what is going on better.
Elige,
I found a better solution which reads all CSV files in a folder:
source_dir = 'C:\Users\borowski.m.3\Documents\BAMs\Fuzzy Logic Control of BAM\BAM 186 Startup Torque Trends'; source_files = dir(fullfile(source_dir, '*.CSV')); for i = 1:length(source_files) BAM_186_Torque_8Nov_Values = xlsread(source_files(i).name,1,'G15:G1014'); end
Only problem I am having now is, how do I put these into a length(source_files) x length('G15:G1014') matrix? (in this case, a 120x1000).
Good job... even better. As to your current problem, all you need to do is initialize your BAM_186_Torque_8Nov_Values martix and fill it like I did above. It looked like you wanted each row of data to represent each G-column data from each CSV file... so you would:
source_dir = 'C:\Users\borowski.m.3\Documents\BAMs\Fuzzy Logic Control of BAM\BAM 186 Startup Torque Trends';
source_files = dir(fullfile(source_dir, '*.CSV'));
M = length(source_files);
N = 1014-15+1; % Hard coded since 'G15:G1014' is hard coded too
BAM_186_Torque_8Nov_Values = zeros(M,N); % Intialize output dataset
for ii = 1 : M
BAM_186_Torque_8Nov_Values(ii,:) = ...
xlsread(source_files(ii).name,1,'G15:G1014')';
end
Let me know if that doesn't work.

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