Index of NaN Values
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Tiago Dias
le 23 Juil 2018
Modifié(e) : Walter Roberson
le 23 Juil 2018
Hello,
My objective is to know the index of NaN values per column.
y = [1,2;NaN,4;5,NaN;7,8;9,NaN]
idx = isnan(y)
for j = 1:m
for i = 1:n
if idx(i,j) == 1
idx_all(i,j) = i
end
end
end
I get a result of
idx_all = 0 0
2 0
0 3
0 0
0 5
I would like the result to be something like
idx = [2 3
0 5]
Because the 1st column has just one NaN on row 2, and the 2nd column has NaN for row 3 and 5.
Thanks.
2 commentaires
jonas
le 23 Juil 2018
Is it really necessary to save the indices in that form? You should read about the find function.
Réponse acceptée
Walter Roberson
le 23 Juil 2018
A loop is easiest.
nc = size(y,2);
idx = zeros(0, nc);
for C = 1 : nc
nidx = find(isnan(y(:,C)));
idx(1:length(nidx), C) = nidx;
end
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