Reading a specific ASCII format file

I have ASCII files in the format uploaded and I would like to read the data below the header [DATA]. Any guidance on how I could do that? The number of columns 3-6 depending on the file and the number of rows might defer as well.

Answer 1

[Hassaan]

% Open the file
filename = 'New Text Document.txt'; % Change to your actual file name
fid = fopen(filename, 'r');

% Initialize a flag to indicate when the [DATA] section starts
data_section_started = false;

% Initialize a cell array to hold the data
data = {};

% Read the file line by line
while ~feof(fid)
    line = fgets(fid); % Read a line
    
    % Check if we've reached the [DATA] section
    if contains(line, '[DATA]')
        data_section_started = true;
        continue; % Skip the line with [DATA]
    end
    
    % If we're in the [DATA] section, read the numbers
    if data_section_started
        % Split the line by tab and convert to numbers
        num_line = str2num(line); %#ok<ST2NM> % This function is appropriate here
        if ~isempty(num_line)
            data{end+1} = num_line; % Append to the data cell array
        end
    end
end

% Close the file
fclose(fid);

% Convert the cell array to a matrix (assuming the data is uniform)
data_matrix = vertcat(data{:});

disp(data_matrix)

1. The file is opened with fopen, and the script reads the file line by line.
2. A flag data_section_started is used to determine when the [DATA] section has started.
3. Each line of numbers is appended to a cell array data as a numeric array.
4. After all data is read, the cell array is concatenated into a matrix with vertcat.

This script assumes that your data is well-formed (all rows have the same number of columns) and that the data is separated by tabs or spaces. If the data is not uniform or if the file uses a different delimiter, you might need to adjust the str2num line accordingly.

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[Hassaan]

@Ashutosh Why not use a JSON format or XML format for organzing your data file.

Answer 2

[Sai Teja G]

Hi Ashutosh,

Please refer to the following code to learn how to read the data situated beneath the '[DATA]' header. Additionally, you can view the output generated from your sample file.

% Open the file for reading
filename = 'your.txt'; % Replace with your actual file name
fileID = fopen(filename, 'r');
% Check if the file was opened successfully
if fileID == -1
    error('File could not be opened.');
end
% Read lines until we find the [DATA] header
while ~feof(fileID)
    line = fgetl(fileID);
    if strcmp(line, '[DATA]')
        break;
    end
end
% Check if we actually found the [DATA] header
if feof(fileID)
    error('No [DATA] header found in the file.');
end
% Read the data below the [DATA] header
% Assuming the data is separated by whitespace and the file does not
% contain text after the numerical data.
data = textscan(fileID, '%f'); % '%f' reads floating point numbers
data = cell2mat(data); % Convert cell array to a matrix
% Close the file
fclose(fileID);
% Reshape the data if necessary
% If the number of columns is known after the header, you can reshape the data.
% For example, if there are 4 columns:
% numColumns = 4;
% numRows = length(data) / numColumns;
% data = reshape(data, [numColumns, numRows])';
display(data);

data = 12×1

1 2 1 1 2 1 1 2 1 1

Answer 3

[Venkat Siddarth Reddy]

Hi Ashutosh,

To solve this query, you can read the file line by line until you find the "[DATA]" header.And then read the data into a matrix,using "textscan" function.

Following is an example code snippet to achieve the above:

filename = 'Test doc.txt';
data = readDataAscii(filename)

data = 4×3

1 2 1 1 2 1 1 2 1 1 2 1

function data = readDataAscii(filename)
    
    fid = fopen(filename, 'rt');

    % Read the file line by line to find the [DATA] header
    foundDataHeader = false;
    while ~feof(fid)
        line = fgetl(fid);
        if strcmp(line, '[DATA]')
            foundDataHeader = true;
            break;
        end
    end
    
    % Check if the [DATA] header was found
    if ~foundDataHeader
        fclose(fid);
        error('No [DATA] header found in file: %s', filename);
    end
    
    % Read the data below the [DATA] header
    % Assuming that the data is numeric and tab-separated
    data = [];
    while ~feof(fid)
        line = fgetl(fid);
        if ~ischar(line) % End of file or empty line
            break;
        end
         numCols = numel(strsplit(line));
        formatSpec = repmat('%f', 1, numCols); % Create format specifier
        lineData = textscan(line, formatSpec, 'Delimiter', ' ', 'MultipleDelimsAsOne', true);
        data = [data; cell2mat(lineData)];
    end
    
    % Close the file
    fclose(fid);
end

I hope it helps!