How to divide timeseries data into seasonal variation

This is the first instant of my data.

DateTime Global_active_power Global_reactive_power Voltage Global_intensity Sub_metering_1 Sub_metering_2 Sub_metering_3

1/01/2007 0:00 2.58 0.136 241.97 10.6 0 0 0

I want to divide it into summe and winter data.

[Guillaume]

What is your definition of summer and winter (when do they start and end)?

[Niraj Acharya]

June, July and August are summer while December, January and February are winter. I have list of date in this form:

DateTime

1/1/2007 0.00

1/2/2007 1.00

1/3/2007 1.10

........

Answer 1

[Guillaume]

Note that if you're indeed using timeseries, you may be better off using timetables instead. They're slightly easier to use and are more powerful.

The following applies to timetables, I believe it's more or less the same syntax for timeseries.

While you can indeed split the data into winter and summer (and discard the rest):

summer = yourtimetable(ismember(month(yourtimetable.DateTime), 6:8), :);  %6 to 8 is June, July, August
winter = yourtimetable(ismember(month(yourtimetable.DateTime), [1, 2, 12]), :);  %1, 2, 12 is January, February, December

you may be better off adding a new variable named Season of type categorical:

yourtimetable.Season = discretize(mod(month(yourtimetable.DateTime), 12), 0:3:12, 'categorical', {'winter', 'spring', 'summer', 'autumn'});  %the mod is to bring december as first month

you can then do group calculation by season with e.g. groupsummary.