MATLAB Answers

Replace NaN with median per column

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Konvictus177
Konvictus177 on 10 Aug 2021
Answered: Yazan on 10 Aug 2021
Hi,
I have a matrix where I have NaN values in a few columns.
I would like to fill the NaN values with the median value of that column. How do I do that?

Answers (4)

KSSV
KSSV on 10 Aug 2021
Edited: KSSV on 10 Aug 2021
Read about fillmissing.
Or USe:
A = rand(20,1) ; % data for demo
A(randperm(20,5)) = NaN ; % insert nans
M = nanmedian(A) ; % get median
A(isnan(A)) = M % replace nans with medians

Wan Ji
Wan Ji on 10 Aug 2021
It is convenient to use fillmissing function to get what you want
matOut = fillmissing(matrixIn, 'linear', 'EndValues','nearest')
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Stephen
Stephen on 10 Aug 2021
Edited: Stephen on 10 Aug 2021
M = randi(3,5,7);
M(randi(numel(M),1,9)) = NaN
M = 5×7
1 NaN 1 1 2 3 1 NaN 1 2 NaN 1 1 3 NaN 3 NaN 1 2 1 NaN 2 NaN 3 2 3 2 2 1 1 2 NaN 1 3 2
V = median(M,1,'omitnan')
V = 1×7
1 1 2 1 2 2 2
X = isnan(M);
M(X) = repelem(V,sum(X,1))
M = 5×7
1 1 1 1 2 3 1 1 1 2 1 1 1 3 1 3 2 1 2 1 2 2 1 3 2 3 2 2 1 1 2 1 1 3 2

Yazan
Yazan on 10 Aug 2021
clc, clear
x1 = randn(5, 5);
x1(randi(numel(x1), 1, 5)) = nan;
x2 = fillmissing(x1, 'movmedian', size(x1,1)*2, 1);
display(x1)
x1 = 5×5
NaN 0.1826 NaN 0.3875 -0.7928 1.3983 -0.1527 0.1261 0.1482 -0.8491 1.4623 0.7005 -0.0511 -0.1259 1.1562 0.8948 0.0311 0.0064 NaN NaN -0.2615 -0.1371 -1.7245 0.9723 0.5918
display(x2)
x2 = 5×5
1.1466 0.1826 -0.0223 0.3875 -0.7928 1.3983 -0.1527 0.1261 0.1482 -0.8491 1.4623 0.7005 -0.0511 -0.1259 1.1562 0.8948 0.0311 0.0064 0.2678 -0.1005 -0.2615 -0.1371 -1.7245 0.9723 0.5918

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