MATLAB: Using ismember to get the corresponding elements

ismemberMATLAB

Hi, I am using a function to convert the time to seconds based on specific input. 'time_data_observation_entry,real_time_vec,frame_vec are column vetors and frame_rate_played_video = 8. time_data_observation_entry have two columns. After performing the 'ismember' operation, i am not able to preserve the real_time corresponding to time_data_observation_entry. It looses the structure of the data. Any help to solve this will be appreciated
time_data_observation = load('time_data_observation.mat')
frame_rate_played_video = 8;
real_time_vec = load('real_time_vec');
frame_vec = load('frame_vec');
function [real_time] = time_from_videos_to_second_convertor(time_data_observation_entry,frame_rate_played_video,real_time_vec,frame_vec)
for ii = 1:length(time_data_observation_entry)
    if isnan(time_data_observation_entry)
        continue
    end
    frame_id = floor(time_data_observation_entry*frame_rate_played_video);
    real_time  = real_time_vec(ismember(frame_vec,frame_id));  
end
end

Best Answer

Like Guillaume already mentioned you did not perform any indexing inside your loop and are just repeating the entire operation every time. What i assumed you wanted to do is:
function [real_time] = time_from_videos_to_second_convertor(time_data_observation_entry,frame_rate_played_video,real_time_vec,frame_vec)
real_time = nan(size(time_data_observation_entry));
for ii = 1:length(time_data_observation_entry)
    if any(isnan(time_data_observation_entry)) % or all instead of any if you only wanna skip if both entries are nan
        continue
    end
    frame_id = floor(time_data_observation_entry(ii,:)*frame_rate_played_video);
    real_time(ii,:)  = real_time_vec(ismember(frame_vec,frame_id));  
end
end
This will return a real_time vector, with the same format as time_data_observation but nans where they the time_data_observations are nans, you can filter them out of the result or inside the function using logical indexing.
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