Saving data from nested loop into final table

Hello all,

I have this code bellow and its repeated for 6 types of vehicles (the one shown bellow is for buses only), and I want to save data from inside the loop such as (frame_bus, local_time_bus, time_steps_bus, x_bus, y_bus, x_cent_bus, y_cent_bus) so the final table should have columns for each of those variables for all vehicles, something like:

column of "frame" = frame_bus + frame_car + frame_motor + frame_trailer + frame_truck + frame_van

column of local_time = local_time_bus + local_time_car + local_time_motor + local_time_trailer + local_time_truck + local_time_van

column of time_steps = time_steps_bus +time_steps_car +time_steps_motor + time_steps_trailer + time_steps_truck +time_steps_van

column of x_veh = x_bus + x_car + x_motor +x_trailer + x_truck + x_van

column of y_veh = y_bus + y_car +y_motor + y_trailer + y_truck + y_van

column of x_cent_veh = x_cent_bus + x_cent_car +x_cent_motor + x_cent_trailer + x_cent_truck +x_cent_van

column of y_cent_veh = y_cent_bus + y_cent_car +y_cent_motor + y_cent_trailer +y_cent_truck +y_cent_van

column ofveh_speed = speed_bus +speed_car + speed_motor +speed_trailer +speed_truck + speed_van

Thanks a lot in advance

%% Buses
Nbuses = length(busesId);
Nbuses_counted = 0;
for j = 1:Nbuses
    buid_j = busesId(j);
    busj = data2(data2.trackId == buid_j, :);
    
    if size(busj, 1) == 0
        continue;
    end
    
    % Get frame
    frame_bus = busj.frame;
%     frame_bus = [frame_bus];
    
    % Get local_time
    local_time_bus = busj.frame/25;
%     local_time_bus = [local_time_bus];

    % Get time steps
    time_steps_bus = (busj.frame(2:end)-busj.frame(1:end-1))./25;
    time_steps_bus = [0;time_steps_bus]; % add zero as the first local time step
    
    % get xy points
    x_bus = busj.xCenter;
    y_bus = busj.yCenter;
%     x_bus = [x_bus];
%     y_bus = [y_bus];

    % Get speed
    speed_bus = sqrt(busj.xVelocity.^2 + busj.yVelocity.^2);
%     speed_bus = [speed_bus];
        
    % Get centroid
    x_cent_bus = busj.width/2;
    y_cent_bus = busj.length/2;
%     x_cent_bus = [x_cent_bus];
%     y_cent_bus = [y_cent_bus];

    interacting_vehicles{v} = sprintf("veh %d", buid_j);
    v = v + 1;
    
       end
    
    uniqueID{uid} = sprintf("R%dB%d", fid, bid);
    uid = uid + 1;

end

Answer 1

[Vijay]

Hi @Reem RA

You can use structure array to store the information and then use strcuct2table to convert them to table.

Please refer the below documentations for more information about structure arrays and struct2table.

Structure Arrays - MATLAB & Simulink - MathWorks India

Convert structure array to table - MATLAB struct2table - MathWorks India

Example for frame:

Frame = struct(); 
%create more structures for centroid, local_time, etc. 
Inside the loop that is processing buses. 
%… your code 
if (isfield(Frame, iframe_bus )) 
Frame.frame_bus = [Frame.frame_bus, frame_busj]; 
else 
    Frame.frame_bus = [frame_busj]]; 
end 

Similarly, you can include this code into loops processing frames belonging to different vehicles. Just change the column name to other attribute like local_time, centroid, etc.

Hope this helps!

[Reem RA]

Thank you so much!!!