How to use textscan to import time value (hh:mm:ss)

I need to import time values in a given column to an array using textscan. I can't seem to be able to find the correct format spec to do this.

Attached is the file I am trying to import from. The row titled 'Start Time" is what I want. The values begin in row 22 column 2 and are in format (hh:mm:ss).

The import data tool uses the below format however gives me rounded values numerical values that are not helpful. How can I edit this to give me what I want

delimiter = ',';
if nargin<=2
startRow = 22;
endRow = 22;
end
formatSpec = '%*s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%[^\n\r]';
dataArray = textscan(fileID, formatSpec, endRow(1)-startRow(1)+1, 'Delimiter', delimiter, 'TextType', 'string', 'HeaderLines', startRow(1)-1, 'ReturnOnError', false, 'EndOfLine', '\r\n');

Answer 1

[Akira Agata]

I think it's better to do it step-by-step, like:

% Read the file
fid = fopen('181018_PL.txt','r');
c = textscan(fid,'%s','Delimiter','\n');
fclose(fid);

% Extract the line starts with 'Start Time'
idx = startsWith(c{1},'Start Time');
str = c{1}{idx};

% Split the line and eliminate 'Start Time'
dataArray = strsplit(str,',');
dataArray(1) = [];

% Convert to datetime
dataArray = datetime(dataArray);

[Guy Burke]

Thank you for your answer but it seems as though the text file imports as a 17579x1 cell, so the time values are not in the row but the subsequent values below start time in the logical idx array.

[Akira Agata]

Seems strange. In your environment, what is the output variable c{1} ? Since delimiter is set to '\n', the input text file will be separated into each line. As a result, c{1} should be 155x1 cell array.

% Read the file
fid = fopen('181018_PL.txt','r');
c = textscan(fid,'%s','Delimiter','\n');
fclose(fid);

[Guy Burke]

It worked! I was using the wrong syntax for the delimiter. Thanks for much!

Answer 2

[Peter Perkins]

This is a row-oriented file, I'll let you figure out how to best get that into MATLAB. But if the question is how to turn those "time of day" timestamps into durations, in R2018a you can just do that:

>> duration({'12:08:59','12:14:00','12:18:59','12:23:59'},'Format','hh:mm:ss')
ans = 
  1×4 duration array
   12:08:59   12:14:00   12:18:59   12:23:59

Prior to that, you can use text2duration from the FEX.