Adding rows to matrix conditionally
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I have long datafiles that I need to alter and cannot figure out how to do this.
The simplified version of what I'm trying to do is:
x = 1 20
3 50
6 10
Column 1 is time (t) (sec 1, 3, 6) and col 2 the values.
I want to create a new matrix with time axis with 1 sec interval and that the values (col 2) are repeated until next (t) ( in col1)
The resulting matrix should be:
x2 = 1 20
2 20
3 50
4 50
5 50
6 10
Sorry about the elementery question, I'm a newby
1 commentaire
Star Strider
le 31 Mar 2020
I will defer to Guillaume’s Answer, since he posted the solution first. The data file is attached.
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Guillaume
le 31 Mar 2020
We don't have enough details to give you a complete answer but what you want to do should be easily done by
- reading your file as a timetable. Could be as easy as:
data = readtimetable(yourfile);
depending on the actual file
- retime the timetable to 1 second interval, which is simply:
resampled = retime(data, 'secondly', 'previous'); %retime in one second interval using the previously known value for the missing times
- save into a new file
writetimetable(resampled, 'newfile.csv');
for example
6 commentaires
Guillaume
le 1 Avr 2020
You can construct a new time vector starting at the time of your choosing and pass that to retime instead of letting it construct it:
newtimes = (tdata.DateTimeUnified(1):seconds(30):tdata.DateTimeUnified(end)+seconds(30))';
resampled = retime(tdata, newtimes, 'previous');
Plus de réponses (1)
Andrei Bobrov
le 31 Mar 2020
out = [(x(1,1):x(end,1))',repelem(x(:,2),[diff(x(:,1));1])];
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