Find specific date/time from a series of datenums
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I have a 7184x72001 double matrix where the first column is a list of serial datenumbers.
I am happy to keep the format this way, but I need to be able to select a specific date/time from this list so that I can extract the data from certain days/times that I am interested in.
So, is it either possible to:
-search from a list of datenums to find a specific date/time that I provide?
-add a column of str data to a matrix of double?
or-convert all of the datenums to date and time?
I have tried the second approach so far:
D=csvread('Tiritiri5280_PSD_1sHammingWindow_50%Overlap_output.csv'); %load in data
t=D(:,1); %extract time column
times=datestr(t, formatOut); %convert t column datenums to date and time
rows=(1:length(times)).'; %number of dates and times we have
D_new=[rows D]; %add new column to D
D_new(:,1)=timeslist(:,2); %add times in different format to D
-this works but I now get the datenum in a different format which is also not readable. How do I keep the date time in yymmddhhmmss in a double matrix? Is this possible?
Here,column 1 is the new dates/times that I tried to insert in readable form, and column 2 is serial datenum.
Steven Lord on 17 Sep 2019
If you're going to be doing a lot of processing of this data based on the times, consider turning your column of date numbers into a datetime array and using that datetime array to convert your data matrix into a timetable. Once you do this you could extract data from the timetable based on the times for each row using a timerange as shown in the "Subscript on Time Range" section on this documentation page. You could also resample or aggregate your timetable data using a certain time basis, as shown here.
More Answers (1)
Ted Shultz on 17 Sep 2019
It looks like the start of your approach is reasonable. Once you make a “times” array, there is no need to add it back to the “D” matrix. You can use that as your index.
indexOfInterest = (times > t_one) && (times < t_two);
someData =d(indexOfInterest, :);