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Sorting data based on time

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Jake il 6 Mar 2020
Commentato: Ameer Hamza il 9 Mar 2020
I have multiple csv files and each looks like this.
First column is an ID and the second one is the time (yyyymmddhhmmss). Here date does not change (yymmdd) but the hours changes. Is it possible to create seperate csv (or txt) files with a time limit?
For example, for one ID, could following files be created?
  • data raws between 00hr and 03hr
  • data raws between 03hr and 06hr
  • data raws between 06hr and 09hr etc.
For instance, if there are no data for a given time period, it either creates no csv file or creates an empty csv file.
Again, I'm trying to explore more with this approach. Any suggestion is appreciated!
  3 Commenti
Jake il 6 Mar 2020
As you can see, the sample starts with a timestamp of 2020-02-21: 07:55:14. Which means the first data raw should belong to a csv (or txt) file that stores data between 06hr and 09hr. And so on.
Thanks a lot! I've been grinding my head over this but I couldn't get to where I need yet.
Ameer Hamza
Ameer Hamza il 6 Mar 2020
Hi James, please check the code in the answer below.

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Ameer Hamza
Ameer Hamza il 6 Mar 2020
Modificato: Ameer Hamza il 6 Mar 2020
You can use readmatrix and writematrix functions to read and write to CSV files. The following code will create partitions of data and create several CSV files.
If you are using R2018b and earlier, you can use the commented lines.
data = int64(readmatrix('Sample.csv'));
% data = int64(csvread('Sample.csv')); % for R2018b and earlier
time = data(:,2);
% remove empty rows
data = data(time>0, :);
time = time(time>0);
time = mod(time, 1000000); % yyyymmdd are not important so discard them
current_time = 60000; % time in hhmmss format
while size(data, 1) > 0
next_time = current_time + 30000; % 30000 represent 3 hours
index = time < (current_time + 30000);
partial_data = data(index, :);
writematrix(partial_data, ...
['data-' num2str(current_time/10000) '-' num2str(next_time/10000) '.csv']);
% dlmwrite(['data-' num2str(current_time/10000) '-' num2str(next_time/10000) '.csv'], ...
% partial_data, 'precision', '%i'); % for R2018b and earlier
data(index,:) = [];
time(index,:) = [];
current_time = current_time + 30000;
  6 Commenti
Jake il 9 Mar 2020
Thank you, Ameer. I think that narrows down the error to something that I've done along the way and I think that might be something related to renaming the files. I can retrace back and fix it.
Thanks again, this has been a great help!
Ameer Hamza
Ameer Hamza il 9 Mar 2020
Glad to be of help.

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