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 Divakar · Accepted Answer · 2014-06-21T04:26:07

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

1 Answers