Problem with retime function

Hello all.

I want to use retime to convert a M15 time table to for example a H1 table.

          DateTime           Open       High        Low       Close     Volume
    ____________________    _______    _______    _______    _______    ______

    26-Aug-2019 00:00:00    0.89545    0.89638    0.89529    0.89638      199 
    26-Aug-2019 00:15:00    0.89638    0.89641    0.89589      0.896      187 
    26-Aug-2019 00:30:00     0.8962    0.89632    0.89574    0.89603      139 
    26-Aug-2019 00:45:00    0.89569    0.89594    0.89542    0.89546      157 

In this case, I should get the followings:

Open = open@26-Aug-2019 00:00:00

Close = close@26-Aug-2019 00:45:00

High = (max(High))

Low = (min(Low))

resulting the below table.

          DateTime           Open       High        Low       Close     Volume
    ____________________    _______    _______    _______    _______    ______

    26-Aug-2019 01:00:00     0.89545   0.89641    0.89529    0.89546    682

However whatever method I used within the retime function, it won't return what I described above.

Any solution to this?!

Answer 1

[Cris LaPierre]

It can be done in pieces. retime applies the same method to all timetable variables. You'll need to create new timetables (only containing the variables you need for each method) and call retime for each method you want to use (first value, max, min, last value, sum) . At the end, combine the smaller time tables together. See this example from the documentation.

If I were to do this with the table you show above, I'd do something like this.

% Create a timetable for each method only containing the variables that method is applied to
M15_open = M15(:,"Open");
M15_high = M15(:,"High");
M15_low = M15(:,"Low");
M15_close = M15(:,"Close");
M15_vol = M15(:,"Volume");

% Retime each timetable
H1_open = retime(M15_open,'hourly','firstvalue');
H1_high = retime(M15_high,'hourly','max');
H1_low = retime(M15_low,'hourly','min');
H1_close = retime(M15_close,'hourly','lastvalue');
H1_vol = retime(M15_vol,'hourly','sum');

% Combine the individual timetables back into a single time table
H1 = [H1_open H1_high H1_low H1_close H1_vol]