Deleting runs of zeros
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Hello! I have a dataset that occasionally has runs of zeros. I would like to delete those runs from my data. How do I state that for any run of 3 or more zeros in my data, I would like Matlab to completely delete those observations from my dataset.
So for example, I have a dataset that looks like
[1 5;2 7;3 0;4 0;5 0;6 3]
I would like the that run of zeros deleted so that my new dataset looks like...
[1 5;2 7;6 3]
Any help is greatly appreciated!!
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Guillaume
2015-5-14
one possible way, use strfind (which works with numbers despite the name). Using a more complex example (to show that it works regardless of the numbers of 0 in the run):
data = [1 5; 2 0; 3 0; 4 2; 5 3; 6 0; 7 0; 8 0; 9 0; 10 1; 11 0; 12 0; 13 0]
startseq = strfind(data(:, 2)', [0 0 0]);
toremove = unique([startseq, startseq+1, startseq+2]);
data(toremove, :) = []
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Joseph Cheng
2015-5-14
you would find the indexes that equal zero then if the number is greater or equal to three then delete them from original like in the example below;
x = [1 5;2 7;3 0;4 0;5 0;6 3]
[r c v]=find(x==0);
if numel(r)>=3
x(r,:)=[];
end
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Stephen23
2015-5-14
@ Joseph Cheng: do not put empty lines in your code, and then this page will format the entire code in one box.
Also while this certainly detects zeros, it does not detect runs of zeros, which by definition must be consecutive. This code does not resolve this issue.
Joseph Cheng
2015-5-14
?when did the page layout change? oh and yes i didn't see the comment on runs of zeros. However quick modification of taking the diff of r (diff(r)) and looking for values of 1, one can determine runs of zeros.
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