how to replace NaN values with zero?

Hello,

I have a matrix of 361*181 dimention, which contain NaN and some values.

I want to replace those NaN values with 0, I have tried A(isnan(A))=0; command but is showing error.

the error read as " Subscript indices must either be real positive integers or logicals".

can anyone help me out this?

[Walter Roberson]

What shows up for

which -all isnan

[Puspa patra]

Thanks

Answer 1

[madhan ravi]

Might happen that your isnan is somehow a variable maybe try the following:

clear all
A(isnan(A))=0;

%%%% an example 
A=rand(3);
A([2 3],2)=NaN;
A(isnan(A))=0;

Gives:

A =

    0.7339    0.8422    0.1934
    0.0039         0    0.3316
    0.1183         0    0.6213

[Puspa patra]

Same error,

By the way there is no difference between your code and mine.

[madhan ravi]

In case if you didn‘t notice mine has clear all at the very beginning which is used to clear the variables from the workspace in case if you have any variable named isnan it will be cleared , this is one way of clearing the error.

[madhan ravi]

Type in command window the following and paste the output here

whos isnan
whos A
which isnan -all 

[Puspa patra]

  Name       Size            Bytes  Class     Attributes

  isnan      1x0                 0  double              

  Name        Size              Bytes  Class     Attributes

  A         361x181            522728  double              

isnan is a variable.
built-in (/usr/local/MATLAB/R2015b/toolbox/matlab/elmat/@double/isnan)     % Shadowed double method
built-in (/usr/local/MATLAB/R2015b/toolbox/matlab/elmat/@uint8/isnan)      % Shadowed uint8 method
built-in (/usr/local/MATLAB/R2015b/toolbox/matlab/elmat/@uint16/isnan)     % Shadowed uint16 method
built-in (/usr/local/MATLAB/R2015b/toolbox/matlab/elmat/@uint32/isnan)     % Shadowed uint32 method
built-in (/usr/local/MATLAB/R2015b/toolbox/matlab/elmat/@uint64/isnan)     % Shadowed uint64 method
built-in (/usr/local/MATLAB/R2015b/toolbox/matlab/elmat/@int8/isnan)       % Shadowed int8 method
built-in (/usr/local/MATLAB/R2015b/toolbox/matlab/elmat/@int16/isnan)      % Shadowed int16 method
built-in (/usr/local/MATLAB/R2015b/toolbox/matlab/elmat/@int32/isnan)      % Shadowed int32 method
built-in (/usr/local/MATLAB/R2015b/toolbox/matlab/elmat/@int64/isnan)      % Shadowed int64 method
built-in (/usr/local/MATLAB/R2015b/toolbox/matlab/elmat/@single/isnan)     % Shadowed single method
built-in (/usr/local/MATLAB/R2015b/toolbox/matlab/elmat/@char/isnan)       % Shadowed char method
built-in (/usr/local/MATLAB/R2015b/toolbox/matlab/elmat/@logical/isnan)    % Shadowed logical method
/usr/local/MATLAB/R2015b/toolbox/matlab/timefun/@duration/isnan.m          % Shadowed duration method
/usr/local/MATLAB/R2015b/toolbox/matlab/timefun/@calendarDuration/isnan.m  % Shadowed calendarDuration method
/usr/local/MATLAB/R2015b/toolbox/symbolic/symbolic/@sym/isnan.m            % Shadowed sym method
/usr/local/MATLAB/R2015b/toolbox/ident/ident/@iddata/isnan.m               % Shadowed iddata method
/usr/local/MATLAB/R2015b/toolbox/ident/nlident/@idnlmodel/isnan.m          % Shadowed idnlmodel method
/usr/local/MATLAB/R2015b/toolbox/ident/nlident/@idnlgrey/isnan.m           % Shadowed idnlgrey method
/usr/local/MATLAB/R2015b/toolbox/distcomp/parallel/@codistributed/isnan.m  % Shadowed codistributed method
/usr/local/MATLAB/R2015b/toolbox/distcomp/gpu/@gpuArray/isnan.m            % Shadowed gpuArray method

[Puspa patra]

this is the output

[Walter Roberson]

isnan is a variable.

That is the important point. You assigned something to isnan at some point, which damages the ability to use isnan() as a function.

[madhan ravi]

See as I told you , it's a variable

The solution is

clear isnan
% or
clear all
% or
clear global

[Puspa patra]

Thanks a lot.... it worked

[madhan ravi]

Anytime :)

[Fabricio Arturo Balboa Cavazos]

Thanks madhan ravi!

[Ashishkumar Gupta]

@madhan ravi

Tried ur code for my problem (https://de.mathworks.com/matlabcentral/answers/1889142-how-to-remove-nans-from-struct) but did not work out!!

I want to replace all the NaN with 0 so that size is same for future use.

[hxen]

Ashishkumar Gupta The png attachments in your linked post are not informative. It might be you are not accessing the structure data correclty to get the value you wish to set to zero.

For example, you have a struct named WS_struct with several fields. To access the values (and assuming they are numeric), you would type: WS_struct.HP_EDU_00571_eTA

Just be sure that the fields give numeric data and you correctly access the data. The data fields in the other pic are double, so the method outlined about should work and you can explore with this code how to manipulate the struct fields and set to new named varibles and access entries:

%% example code to set all nan entries to zero after accessing from a struc file

clear all; clc;

M = 5*rand(5,5); % make a 5x5 matrix with random nums on [0,5]

n = randi([1 3],1); % rand num from 1 to 3 to use as the num of nans

randRows = randi([1 5],n,1); % get n rand rows from the 5 cols

randCols = randi([1 5],1,n); % get n rand cols from the 5 cols

fprintf('\nA random 5x5 matrix with 1 to 9 random nan entries:\n');

M(randRows,randCols) = nan

% Now create a structure with field randM and set to M

S.randnum = n;

S. randRows = randRows

S. randCols = randCols;

S.randM = M;

save('randomMatrix.mat','S'); % save structure S

% clear all memory and access data directly from struct S

clear all; % mimicking someone handing you the structure for the first time

load randomMatrix.mat

% set matrix newM to S.randM

newM = S.randM;

fprintf('\nSetting all nan entries to zero:\n');

newM(isnan(newM)) = 0 % find nan entries and set to zero