Selecting rows of data between time and date range in tall array in matlab

Question

I'm applying tall arrays to a couple of .csv files. The tall array looks like:

  Timestamp           wind_spd_sd    wind_spd_mx
___________________    ___________    ___________

04/03/2016 00:00:01    0.57576        4.1        
04/03/2016 00:03:01    0.53692        3.1        
04/03/2016 00:06:01    0.35642        4.2        
04/03/2016 00:09:01    0.63012        4.9        
04/03/2017 00:12:01    0.30357        3.7        
04/03/2017 00:15:01    0.53442        10        
:                      :              :
:                      :              :

I want to be able to select the rows of data between specific dates and times. I came across "timerange" which is used for timetables and used it as:

S1 = timerange('01/01/2015 08:00:00','12/18/2016 12:00:00')

S2 = tt{S1,:}

but had the error: "Subscripting using TIMERANGE is only supported for selecting rows of a timetable."

I then tried using datenum as:

t_start = datenum('04/03/2014 00:00:01', 'dd/MM/yyyy HH:mm:ss');

t_end = datenum('04/03/2015 00:03:01', 'dd/MM/yyyy HH:mm:ss');

rows = find(tt.Timestamp>t_start)

and the error was: "Undefined function 'find' for input arguments of type 'tall'"

I'm not 100% sure if the problem is definitely tall arrays or that I'm making a mistake in how I use these functions. Is there a way to do what I'm trying to achieve here with tall array?

If the posted answer solves your problem, consider marking it accepted by clicking ✔, on the left side of the answer, to turn it green so that the community may know that your problem is solved. — Sardar Usama
– Sardar Usama, Commented May 15, 2017 at 17:24

user2831602 · Accepted Answer · 2017-04-27 17:13:52Z

2

You were on the right track with your use of the timerange function. However, you need to convert your tall array to a timetable, which is a specific data type. Do this first:

TT = table2timetable(tt);
S1 = timerange('01/01/2015 08:00:00','12/18/2016 12:00:00')
S2 = TT(S1,:);

answered Apr 27, 2017 at 17:13

user2831602

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1 Comment

minomi Over a year ago

Thank you. Very helpful.

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