Getting NaN when converting string to number

Hi, I am reading the first line of 4 text files and trying to convert the second column in each file name to a number as i have time stored in the second column. When i convert the second row of elements to number, i am getting NaN. Screen shot of first line of a text file is attached. Any help to solve this will be appreciated.

first_row_of_text_file  = cell(number_of_files,1);
for ii = 1:number_of_files
    fileID = fopen(filenames{ii},'r');
    varNames = textscan(fileID, format, 1, 'Delimiter', delimiter, 'MultipleDelimsAsOne', true, 'TextType', 'string',  'ReturnOnError', false); 
    first_row_of_text_file{ii} = str2double(varNames(:,2));
 end

[Stephen23]

@Hari Krishnan: please upload a sample file by clicking the paperclip button.

[Hari krishnan]

added the file.

[jonas]

How do you want to convert 13:00:02.754000 to a number? What is your desired output?

[Hari krishnan]

I just want to convert this string to a numeric form so that i can do arithmetic operations.

[jonas]

How do you write 13:00:02.754000 in numeric form? I mean, let's say:

A=13:00:02.754000
out=A/2

What is the expected answer?

You may want to look into converting it to a datetime or datenum (double)

Finally, in your previous questions (see e.g. this one ), you already converted the entire textfile to a MATLAB table. Why are you even still working with this text file?

[Walter Roberson]

Or into a duration.

[Hari krishnan]

What i want to do is to take the time from the first row and substract this from the time in the successive rows. So i can get a column with increasing time rather than the time stamp itself.

[jonas]

Then you can convert the string to either a duration or datetime. After subtraction, the format will be duration regardless. In this case I'd suggest going for duration directly as you don't have any date in the same cell.

I still don't understand why you don't use the timetable that I helped you build some days ago. It would be extremely easy to calculate the time difference.

Answer 1

[Kuifeng Zhao]

I suggest change the brackets (),[], into comma ',', and then try to read the data again. Anyway, you can try the function and make necessary changes: importdata('data.txt').