# 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

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]),:) = [];
Evan on 20 Oct 2014
thank you very much works exactly as needed

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)