Help with efficient way of importing data file with specific structure

Hi, I would like some help to implement an efficient way to import data files with a specific structure to Matlab.

An example of the file I want to import is attached and a figure with some details is presented bellow. The main characteristics are:

1) The first row indicates the numer of variables involved (let's say N).

2) The following N rows indicates the name of the variables.

3) The remainig rows contains the data, which are organized as follows:

a) Each row has a maximum of 6 values (or columns). In this example, where we have 22 variables, 4 rows will be needed (6 + 6 + 6 + 4) to represent the first value for each variable.

b) All variables have the same numer of data.

c) The order of the data is the same of the variables.

The number of variables and associated data can change from file to file, but this structure of the file is always the same.

I was thinking that a cell variable would be a good way to work with the data within Matlab. In this case, this variable would be {22,2}, where the first column would be strings with the data label and the second column would be an array with the data itself.

Could someone help me with this?

Answer 1

[Walter Roberson]

filename = 'appropriate_name';

fid = fopen(filename);
nvars = fscanf(fid, '%f', 1);
tdata = textscan(fid, '%[^\n]\n', nvars);
varnames = tdata{1};
fmt = repmat('%f', 1, nvars);
tdata = textscan(fid, fmt);
vardata = cell2mat(tdata);
fclose(fid);

Now varnames is a cell array of character vectors containing everything on the variable lines (possibly including carriage return), and vardata is a something-by-number-of-variables numeric array.

[Bernard Küsel]

Thank you for your answer, Walter!

However, it didn't quite work. As shown in the figure bellow, the data is being read as if all the values were in a single row. As mentinoned in my original question, the data is presented in "blocks", as each row is limited to 6 columns. In this example case, where there are 22 variables, the first data for each variable must be read from the 4 first rows of data.

Could you help me adapt your solution to this scenario?

[Walter Roberson]

Please post a sample data file to test with. It is difficult to test with only pictures of data files.

[Bernard Küsel]

The sample data file "Data.txt" is attached to the original question.

[Walter Roberson]

filename = 'Data.txt';

[fid, msg] = fopen(filename);
if fid < 0
    error('could not open file "%s" because "%s"', filename, msg);
end
nvars = fscanf(fid, '%f', 1);
tdata = textscan(fid, '%[^\n]\n', nvars);
varnames = tdata{1};
fmt = repmat('%f', 1, nvars);
tdata = textscan(fid, fmt, 'delimiter', '\n');
vardata = cell2mat(tdata);
fclose(fid);

[Bernard Küsel]

Perfect! Thank you, Walter!!