Matlab: Import multiple numeric csv .txt files into single cell array

Question

I have multiple (say N of them) .txt files consisting of numeric csv data in matrix form. I would like to import each of these data files into one (1 x N) cell array, whilst preserving the original matrix form. If the original data is small, say 3x3, then textscan does the job in the following manner:

fileId = fopen('data1.txt');
A{1} = textscan(fileID, '%d %d %d', 'delimiter',',','CollectOutput',1);

(This will be part of a function.) But what if my .txt files have 100 columns of data? I could write '%d' 100 times in the formatSpec, but there must be a better way?

This seems to be an easy problem, but I'm quite new to Matlab and am at a loss as to how to proceed. Any advice would be much appreciated, thanks!!

Divakar · Answer 1 · 2014-06-21T05:38:37.330

For such cases with consistent data in each of those text files, you can use importdata without worrying about format specifiers. Two approaches are discussed here based on it.

Approach 1

filenames = {'data1.txt' 'data2.txt' 'data3.txt'}; %// cell array of filenames
A = cell(1,numel(filenames)); %// Pre-allocation
for k = 1:numel(filenames)
    imported_data = importdata(char(filenames(k)));
    formatted_data = cellfun(@str2num, imported_data, 'uni', 0);
    A{k} = vertcat(formatted_data{:})
end

Approach 2

Assuming those text files are the only .txt files in the current working directory, you can directly get the filenames and use them to store data from them into a cell array, like this -

files = dir('*.txt');
A = cell(1,numel(files)); %// Pre-allocation
for k = 1:numel(files)
    imported_data = importdata(files(k).name);
    formatted_data = cellfun(@str2num, imported_data, 'uni', 0)
    A{k} = vertcat(formatted_data{:})
end

Matlab: Import multiple numeric csv .txt files into single cell array

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