Read data from a complex file

Hi Help,

I'm trying to read the data from this kind of file. Here the headers repeat randomly at various rows and first column data is date of the year. I tried using load and readmatrix functions, but no luck. Any thoughts?

Data file has four columns. First column data is day (mm-dd-yy). Header labels from each row repeats across the file but not periodically.

header header2 header3 header4

4-25-16 5 6 7

4-25-16 24 2 25

header header2 header3 header4

4-25-16 52 62 72

4-25-17 2 24 2

4-25-18 52 62 72

4-25-19 25 26 28

header header2 header3 header4

4-25-19 52 62 72

header header2 header3 header4

4-25-19 52 62 72

4-25-20 2 24 2

4-25-21 52 62 72

4-25-22 25 26 28

4-25-23 5 6 7

4-25-24 24 2 25

header header2 header3 header4

4-25-24 5 6 7

4-25-25 24 2 25

Answer 1

[Voss]

Something like the following may work. You may need to change the header_str and text_scan_format to match your actual file's contents.

% path to the file:
file_name = 'file.txt';

% lines in the file starting with header_str will be skipped:
header_str = 'header';

% format of data lines:
text_scan_format = '%d-%d-%d %d %d %d';

% show file's contents, for reference:
type(file_name);

header  header2  header3  header4    
4-25-16  5  6  7    
4-25-16  24  2  25    
header  header2  header3  header4    
4-25-16  52  62  72    
4-25-17  2  24  2    
4-25-18  52  62  72   
 4-25-19  25  26  28    
header  header2  header3  header4   
4-25-19  52  62  72    
header  header2  header3  header4   
 4-25-19  52  62  72    
4-25-20  2  24  2    
4-25-21  52  62  72    
4-25-22  25  26  28    
4-25-23  5  6  7    
4-25-24  24  2  25    
header  header2  header3  header4    
4-25-24  5  6  7    
4-25-25  24  2  25 

% initialize an empty datetime array dt and an empty 3-column matrix vals:
dt = NaT(0,1);
vals = zeros(0,3);

% open the file for reading:
fid = fopen(file_name,'r');

% while not at the end of the file:
while ~feof(fid)
    
    % get the next line:
    str = fgetl(fid);
    
    % if it starts with header_str, skip it:
    if startsWith(str,header_str)
        continue
    end
    
    % read the date and other values from the line:
    temp = textscan(str,text_scan_format);
    
    % put the date in a new elements in the dt array:
    dt(end+1,:) = datetime(temp{[3 1 2]}); % year, month, day
    
    % put the other values in a new row in the vals matrix:
    vals(end+1,:) = [temp{4:6}];
    
end

% close the file:
fclose(fid);

% put dt and vals together in a table:
T = addvars(array2table(vals),dt,'Before','vals1')

T = 15×4 table
        dt         vals1    vals2    vals3
    ___________    _____    _____    _____

    25-Apr-0016      5        6        7  
    25-Apr-0016     24        2       25  
    25-Apr-0016     52       62       72  
    25-Apr-0017      2       24        2  
    25-Apr-0018     52       62       72  
    25-Apr-0019     25       26       28  
    25-Apr-0019     52       62       72  
    25-Apr-0019     52       62       72  
    25-Apr-0020      2       24        2  
    25-Apr-0021     52       62       72  
    25-Apr-0022     25       26       28  
    25-Apr-0023      5        6        7  
    25-Apr-0024     24        2       25  
    25-Apr-0024      5        6        7  
    25-Apr-0025     24        2       25  

[Research]

Thank you. It is an elegant solution.

[Voss]

You're welcome! And thank you!