Function to fill an array given conditions.
显示 更早的评论
Hi All,
I am trying to write a function to fill an array given conditions. basiclly the user inputs two variables a max and min and given these
values it creates two new row vectors, ph and date, which is a subset of an orignal vector.
My code is given below -
function [datenew,phnew] = subsetdata(date, ph, pressure, min, max)
%create empty array
datenew=cell(1,5000);
phnew=cell(1,5000);
%loop through each point
for i=1:size(pressure)
%check condition
if (pressure(i,:)>=min & pressure(i,:)<max)
%fill array if condition met
datenew{i}=date(i);
phnew{i}=ph(i);
end
end
end
2 个评论
Andrew Czeizler
2019-3-13
编辑：Andrew Czeizler
2019-3-13
Adam
2019-3-13
What is your question?
Also, never use min and max as variable names. These are function names in Matlab and by creating variables with those names you hide the respective functions and make them inaccessible to use.
采纳的回答
validIdx = pressure >= minVal & pressure < maxVal;
datenew = date( validIdx );
phnew = ph( validIdx );
should do this for you without needing the loop and using logical indexing instead. I don't know why you are putting results in a cell array though. Never use a cell array when a numeric array will do the job.
2 个评论
Andrew Czeizler
2019-3-13
编辑：Andrew Czeizler
2019-3-13
Adam
2019-3-13
Ah, well, if you want to keep positions with NaNs inbetween then you will need to do it slightly different:
datenew = nan( size( date ) );
phnew = nan( size( date ) );
validIdx = pressure >= minVal & pressure < maxVal;
datenew( validIdx ) = date( validIdx );
phnew( validIdx ) = ph( validIdx );
更多回答（1 个）
Andrew Czeizler
2019-3-13
0 个投票
3 个评论
Adam
2019-3-13
See my reply above.
Andrew Czeizler
2019-3-13
Adam
2019-3-13
If you want to retain the positions within the array then yes. You could use -1 if all true data should be positive, but NaN is more logical.
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