tutorial_global_oce_latlon/diags_matlab/nanmean.m

function y = nanmean(x)
%NANMEAN Average or mean ignoring NaNs.
%   NANMEAN(X) returns the average treating NaNs as missing values.  
%   For vectors, NANMEAN(X) is the mean value of the non-NaN
%   elements in X.  For matrices, NANMEAN(X) is a row vector
%   containing the mean value of each column, ignoring NaNs.
%
%   See also NANMEDIAN, NANSTD, NANMIN, NANMAX, NANSUM.

%   Copyright 1993-2000 The MathWorks, Inc. 
%   $Revision: 1.1 $  $Date: 2002/10/22 13:30:40 $
%
% $Header:  $
% $Name:  $

if isempty(x) % Check for empty input.
    y = NaN;
    return
end

% Replace NaNs with zeros.
nans = isnan(x);
i = find(nans);
x(i) = zeros(size(i));

if min(size(x))==1,
  count = length(x)-sum(nans);
else
  count = size(x,1)-sum(nans);
end

% Protect against a column of all NaNs
i = find(count==0);
count(i) = ones(size(i));
y = sum(x)./count;
y(i) = i + NaN;
1	function y = nanmean(x)
2	%NANMEAN Average or mean ignoring NaNs.
3	% NANMEAN(X) returns the average treating NaNs as missing values.
4	% For vectors, NANMEAN(X) is the mean value of the non-NaN
5	% elements in X. For matrices, NANMEAN(X) is a row vector
6	% containing the mean value of each column, ignoring NaNs.
7	%
8	% See also NANMEDIAN, NANSTD, NANMIN, NANMAX, NANSUM.
9
10	% Copyright 1993-2000 The MathWorks, Inc.
11	% $Revision: 1.1 $ $Date: 2002/10/22 13:30:40 $
12	%
13	% $Header: $
14	% $Name: $
15
16	if isempty(x) % Check for empty input.
17	y = NaN;
18	return
19	end
20
21	% Replace NaNs with zeros.
22	nans = isnan(x);
23	i = find(nans);
24	x(i) = zeros(size(i));
25
26	if min(size(x))==1,
27	count = length(x)-sum(nans);
28	else
29	count = size(x,1)-sum(nans);
30	end
31
32	% Protect against a column of all NaNs
33	i = find(count==0);
34	count(i) = ones(size(i));
35	y = sum(x)./count;
36	y(i) = i + NaN;