nanmedian

(Not recommended) Median, ignoring NaN values

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nanmedian is not recommended. Use the MATLAB® function median instead. With the median function, you can specify whether to include or omit NaN values for the calculation. For more information, see Version History.

Syntax

y = nanmedian(X)
y = nanmedian(X,'all')
y = nanmedian(X,dim)
y = nanmedian(X,vecdim)

Description

y = nanmedian(X) is the median of X, computed after removing NaN values.

For vectors x, nanmedian(x) is the median of the remaining elements, once NaN values are removed. For matrices X, nanmedian(X) is a row vector of column medians, once NaN values are removed. For multidimensional arrays X, nanmedian operates along the first nonsingleton dimension.

example

y = nanmedian(X,'all') returns the median of all elements of X, computed after removing NaN values.

y = nanmedian(X,dim) takes the median along the operating dimension dim of X.

y = nanmedian(X,vecdim) returns the median over the dimensions specified in the vector vecdim, computed after removing NaN values. Each element of vecdim represents a dimension of the input array X. The output y has length 1 in the specified operating dimensions. The other dimension lengths are the same for X and y. For example, if X is a 2-by-3-by-4 array, then nanmedian(X,[1 2]) returns a 1-by-1-by-4 array. Each element of the output array is the median of the elements on the corresponding page of X.

example

Examples

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Open Live Script

Find the column medians for matrix data with missing values.

X = magic(3);
X([1 6:9]) = NaN
X = 3×3

   NaN     1   NaN
     3     5   NaN
     4   NaN   NaN


y = nanmedian(X)
y = 1×3

    3.5000    3.0000       NaN
Open Live Script

Find the median of a multidimensional array over multiple dimensions.

Create a 3-by-5-by-2 array X with some missing values.

X = reshape(1:30,[3 5 2]);
X([10:12 25]) = NaN
X = 
X(:,:,1) =

     1     4     7   NaN    13
     2     5     8   NaN    14
     3     6     9   NaN    15


X(:,:,2) =

    16    19    22   NaN    28
    17    20    23    26    29
    18    21    24    27    30

Find the median of each page of X by specifying dimensions 1 and 2 as the operating dimensions.

ypage = nanmedian(X,[1 2])
ypage = 
ypage(:,:,1) =

    6.5000


ypage(:,:,2) =

   22.5000

For example, ypage(1,1,1) is the median of the non-NaN elements in X(:,:,1).

Find the median of the elements in each X(:,i,:) slice by specifying dimensions 1 and 3 as the operating dimensions.

ycol = nanmedian(X,[1 3])
ycol = 1×5

    9.5000   12.5000   15.5000   26.5000   21.5000

For example, ycol(4) is the median of the non-NaN elements in X(:,4,:).

Extended Capabilities

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Version History

Introduced before R2006a

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See Also

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