Take values greater than 0 excluding NaN

Question

federico nutarelli 2022-7-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1765250-take-values-greater-than-0-excluding-nan

回答： Steven Lord 2022-7-21

Hi all, I have a matrix A, say, like this:

NaN	NaN	1
NaN	-2	-3
NaN	NaN	NaN
2	NaN	-3
NaN	-3	-3
1	-1	2

and would like to make a dummy matrix out of A having values 1 for values that are greater than 0 but ignoring missing values. In other words the expected result is:

NaN	NaN	1
NaN	0	0
NaN	NaN	NaN
1	NaN	 0
NaN	0	0
1	0   1

I tried this:

A=A(~isnan(A))>0

but it provides a vector while I would like a matrix of the same dimensions as A.

Thank you

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Steven Lord 2022-7-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1765250-take-values-greater-than-0-excluding-nan#answer_1012515

在 MATLAB Online 中打开

A = [NaN	NaN	1;
NaN	-2	-3;
NaN	NaN	NaN;
2	NaN	-3;
NaN	-3	-3;
1	-1	0] % Adding an explicit 0
A = 6×3
   NaN   NaN     1
   NaN    -2    -3
   NaN   NaN   NaN
     2   NaN    -3
   NaN    -3    -3
     1    -1     0
B = A;
B(B <= 0) = 0;
B(B > 0) = 1
B = 6×3
   NaN   NaN     1
   NaN     0     0
   NaN   NaN   NaN
     1   NaN     0
   NaN     0     0
     1     0     0

Or:

C = discretize(A, [-Inf, eps(0), Inf], [0, 1])
C = 6×3
   NaN   NaN     1
   NaN     0     0
   NaN   NaN   NaN
     1   NaN     0
   NaN     0     0
     1     0     0

For this last approach anything in the interval [-Inf, eps(0)) (which includes 0; the fact that the right edge is not included is why I used eps(0) instead of 0) becomes 0. Anything in the interval [eps(0), Inf] (this last bin includes both left and right edges) becomes 1. Anything in neither of those intervals (aka NaN) becomes NaN.

If you want an explicit 0 in A to be a 1, use 0 instead of eps(0) in the second input.