How to remove duplicate NaN values from an X Y data set

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Evan on 20 Oct 2014
Commented: Evan on 20 Oct 2014
I have a large data set a simplified version is data=[1,2;3,4;nan,nan;5,6;nan,nan;nan,nan;10,11]. I need to remove any rows of NaN that are repeated more than once so the above example would become data=[1,2;3,4;nan,nan;5,6;nan,nan;10,11]. The sequence is important
1 2
3 4
NaN NaN
5 6
NaN NaN
NaN NaN
10 11
should become
1 2
3 4
NaN NaN
5 6
NaN NaN
10 11
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Accepted Answer

Andrei Bobrov on 20 Oct 2014
Edited: Andrei Bobrov on 20 Oct 2014
data=[1,2;3,4;nan,nan;5,6;nan,nan;nan,nan;7,8];
d = all(isnan(data),2);
n = [0;diff(d)];
k = find(n == -1);
m = find(n == 1);
d = d + 0;
d(k) = m(1:numel(k)) - k;
out = data(cumsum(d) <= 1,:)
other way
data=[1,2;3,4;nan,nan;5,6;nan,nan;nan,nan;7,8];
d = all(isnan(data),2);
data(strfind(d(:)',[1,1]),:) = [];
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Evan on 20 Oct 2014
thank you very much works exactly as needed

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More Answers (1)

Hikaru on 20 Oct 2014
There might be more efficient ways to do this, but the following code works.
data=[1,2;3,4;nan,nan;5,6;nan,nan;nan,nan;10,11]
data(isnan(sum(data,2)),:)=[]
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Hikaru on 20 Oct 2014
Sorry, didn't catch that earlier. Maybe you can use this approach.
a=[1,2;3,4;nan,nan;5,6;nan,nan;nan,nan;10,11];
[r,c] = size(a)
b = reshape(a,1,r*c)
ind = isnan(a(:))'
repeatednan = strfind([0, ind], [1 1])
b(repeatednan)=[]
reshape(b,r-length(repeatednan)/2,c)

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