MATLAB Answers

how can I find a specific data in time table in matlab?

14 views (last 30 days)
I am trying to extract the freez-thaw cycles in a timetable.freezing of stone only occur when the temperature drops below3 °C in a day and thawing when temperature rises above 1 °C in next day. My quastion is that how can I define a function for it and then retime the time table based on it.
I need to find the days with mean temperature below3 °C, followed by a day with mean temperature above 1 °C.(meteorological data file in attachment.)

Accepted Answer

Andrei Bobrov
Andrei Bobrov on 17 Oct 2019
Edited: Andrei Bobrov on 18 Oct 2019
i = diff(3*(data_mean_daily.tabrizmat7 < -3) + (data_mean_daily.tabrizmat7 > 1)) == -2;
T_out = data_mean_daily([i;false]|[false;i],:);
as at Sebastian:
i = (data_mean_daily.tabrizmat7(1:end-1) < -3) & (data_mean_daily.tabrizmat7(2:end) > 1);
T_out = data_mean_daily(find(i(:)')+[0;1],:);
Andrei Bobrov
Andrei Bobrov on 18 Oct 2019
k = 3*(data_mean_daily.tabrizmat7 < -3) + (data_mean_daily.tabrizmat7 > 1);
k is the vector of days, if the element has a value of 3, then the temperature of this day is less than -3, if the value is 1, the temperature is more than +1. We are looking for a combination in our case [3; 1] or diff([3;1]).

Sign in to comment.

More Answers (1)

Sebastian Bomberg
Sebastian Bomberg on 17 Oct 2019
You can offset temperature by one day and compare against >= 4.
idx = data_mean_daily.tabrizmat7(1:end-1) >= 2 & ... % temp at current day greater 2 AND
data_mean_daily.tabrizmat7(2:end) >= 4; % temp at next day greate 4
idx has one row less than data_mean_daily but the missing last row will be treated as false anyway.





Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!