Loading multiple .mat files by using for loop
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Hello, I am trying to load some .mat files and run some specific commands on. The .mat files are named as the following:
% Data Files
dataset1_1.mat dataset2_1.mat dataset3_1.mat ...and so on
dataset1_2.mat dataset2_2.mat ...and so on
dataset1_3.mat ...and so on
...and so on
I want to first load all the dataset1_*.mat files and then perform some calculations on each of them in order (i.e. perform calculations on dataset1_1.mat, then dataset1_2.mat...and so on).
After completing all of the dataset1_*.mat files, I would like to move onto the next batch of files, dataset2_*.mat, and repeat(i.e. perform calculations on dataset2_1.mat, then dataset2_2.mat...and so on).
Process will continue until the last dataset*_*.mat file.
Here is my code so far
% code
files = dir('dataset*_1.mat');
for i = length(files)
files2 = dir('dataset(i)_*.mat');
for j = 1:length(files2)
a = load(files2(j).name);
%Perform some calculations on dataset
end
end
I am using 2 for loops, not sure where I am going wrong. Thanks for the help!
采纳的回答
the line
_files = dir('dataset*_1.mat');_
returns dataset1_1, dataset2_1,... not what you want. then
files2 = dir('dataset(i)_*.mat')
will return nothing, because (i) is not interpreted, you're asking for a file exactly named 'dataset(i)_*.mat'.
you should do something like
% number of set (dataset1, dataset2, ...if unknown, figure it out).
NumberOfDataset = 3;
for i = 1:NumberOfDataset
% get allfiles matching the pattern 'dataset(i)_*'
files = dir(sprintf('dataset%d_*.mat',i));
for j = 1:length(files)
fprintf('Current file : %s\n',files(j).name)
a = load(files(j).name);
%Perform some calculations on dataset
end
end
6 个评论
Guillaume
2014-11-6
Orion, the first dir makes sense, it allows to retrieve the number of prefixes, i.e. finding the NumberOfDataset in your example.
Both approaches are a bit brittle though. What if a number is mising in the middle of a set? You then have a mismatch between your loop count and true file number.
Orion
2014-11-6
@Guillaume
I agree with you, the line
files = dir('dataset*_1.mat');
can be used to determine the number of dataset (what i meant by figure it out). maybe i was not enough clear.
so at the end :
% number of set
files_1 = dir('dataset*_1.mat');
NumberOfDataset = length(files_1);
for i = 1:NumberOfDataset
% get allfiles matching the pattern 'dataset(i)_*'
files = dir(sprintf('dataset%d_*.mat',i));
for j = 1:length(files)
fprintf('Current file : %s\n',files(j).name)
a = load(files(j).name);
%Perform some calculations on dataset
end
end
And about your 2nd comment, if there is a missing file, there will obviously be some trouble, but that's another problem.
Tasadduq
2014-11-6
Guillaume
2014-11-6
Personally, I would extract the numbers from the file names, sort them, and iterate over these real numbers rather than a count of them. This way you would avoid (or detect) problems when a file is missing.
Tasadduq
2014-11-6
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