Better work through indecies in a for loop

Question

Poison Idea fan 2022-9-13

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1804465-better-work-through-indecies-in-a-for-loop

评论： Poison Idea fan 2022-9-13

I use a for loop to compute the absorption of aerosol particles in time series data. I indicate the start and stop of sample time with indecies stored in two arrays. When I compute the absorption I average four minutes of filter time and I do it based on going backwards in index. I run into a problem when the filter time isn't long enough to go back four minutes in time. My work around is using an if statement but it seems cumbersome to do it the way I have below. Is there a better way to do this?

The code below is just meant to be an example. I don't have a workspace small enough to upload to run the code.

for n = 1:length(start0)

if start0(n)-240 < 360 % If the filter time is not big enough then move on to the next sample time

n = n+1;

if start0(n)-240 < 360 % if the second filter time is too small move on to the third

n = n+1;

end

else

n = n;

end

absorption(start0(n):stop0(n),:) = ...

((smoothed_data_table.('Signal')(start0(n):stop0(n),:))...

-mean(smoothed_data_table.('Signal')(start0(n)-250:start0(n)-10,:),1,'omitnan'))...

./(smoothed_data_table.('power')(start0(n):stop0(n),:) .* mic_cal);

ext(start0(n):stop0(n),:) = (rL(1,:)/c).* ...

((smoothed_data_table.('Tau')(start0(n):stop0(n),:).^-1)...

-(mean(smoothed_data_table.('Tau')(start0(n)-250:start0(n)-10,:),'omitnan')).^-1);

end

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Answer 1

David Hill 2022-9-13

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1804465-better-work-through-indecies-in-a-for-loop#answer_1052695

在 MATLAB Online 中打开

Just use continue.

for n = 1:length(start0)
    
    if start0(n)-240 < 360 % If the filter time is not big enough then move on to the next sample time
        continue;
    end
    
    
    absorption(start0(n):stop0(n),:) = ...
       ((smoothed_data_table.('Signal')(start0(n):stop0(n),:))...
       -mean(smoothed_data_table.('Signal')(start0(n)-250:start0(n)-10,:),1,'omitnan'))...
        ./(smoothed_data_table.('power')(start0(n):stop0(n),:) .* mic_cal);
    
    
    ext(start0(n):stop0(n),:) = (rL(1,:)/c).* ...
        ((smoothed_data_table.('Tau')(start0(n):stop0(n),:).^-1)...
        -(mean(smoothed_data_table.('Tau')(start0(n)-250:start0(n)-10,:),'omitnan')).^-1);
end