How to index txt file

Hi everyone,

So I have data comming in at different frequencies in a txt file. I need to be able to index or filter through the data to only give me the data at 60 hz and delete the rows that are coming it at a higher frequency. The first column in the data is time in miliseconds which i have been using to filter the data to 60 hz. So basically I have make do an angorithum that will pick data points at x interval and exclude the other points,

time = data(:,1) ; % time column 
datalength = length(data);
datalength2 = datalength - 1 ; 
A = time(1:datalength2,1); % time data excluding last point 
B = time(2:datalength,1); % time data excluding first point 
C= B-A; % the vector that has the interval between each point   
if C < 16 
    disp(' I < 16, deleting row')
    % deleting row data(#of row,:) = []  
else 
    disp(' I >= 16, keeping row')
end    

this is what I have so far but i know it is wrong cause I can not get it to loop, and I do not know how to identify the row and delete the whole thing. I also have the txt file being imported as a matrix

Please let me know if you have any ihelp!

Answer 1

[dpb]

datalength = length(data);
datalength2 = datalength - 1 ; 
A = time(1:datalength2,1); % time data excluding last point 
B = time(2:datalength,1); % time data excluding first point 
C= B-A; % the vector that has the interval between each point   

is more easily written in MATLAB as

dt=diff(time);      % where I've named your variable C dt for 'delta-t'

which could also be

dt=diff(data(:,1));  % without the temporary time variable; use original

We don't have the input file to see, but one suspects

ttData=readtimetable('yourfile');
Fs=60;
ttD60=retime(ttData,'regular',method,'SampleRate',Fs);

should do it...

[Sophia Starzynski]

it is giving me an error that it is unable to detect datetime or duration data in file

[dpb]

Well, we can't see the file, so as noted it was a guess...what's the input form? Easiest would be to attach the input file.