Missing data values with interpolation

Hello everybody,

I have a cell array each containing a sequence of diferent values. The sequences contains some missing values (I've represented with NaN). I would like to replace all this NaN places with numbers. I think the better way is do an interpolation but I don't know how to code this Nan and how to save it on a table in Matlab.

I1= interp1(x,y,'linear');

Greetings,

Pd) I've tried this but it doesn't work

nanData = isnan(y);
index   = 1:numel(y);
data2   = y;
data2(nanData) = interp1(index(~nanData), y(~nanData), index(nanData));

Answer 1

[Azzi Abdelmalek]

x={ 1  2  3  4  5  6  7  8 9 10}
y={ 0.3850 NaN  3.0394 NaN  0.6475  1.0000  1.5000  NaN  1.1506  0.58}
x=cell2mat(x);y=cell2mat(y);
xi=x(find(~isnan(y)));yi=y(find(~isnan(y)))
result=interp1(xi,yi,x,'linear')

[Emmanuelle]

Thanks Azzi. I see it works with your example but I receive the following message:

??? Cell contents reference from a
non-cell array object.

Error in ==> cell2mat at 44
cellclass = class(c{1});

I've checked the brackets and also the line 44 but there's nothing unusual.

This is the code:

load doc1.txt
x= doc1(:,1);
y= doc1(:,2);
% mxy= [m1x,m1y];

x=cell2mat(x);y=cell2mat(y);
xi=x(find(~isnan(y));yi=y(find(~isnan(y))
result=interp1(xi,yi,x,'linear'

I'm going to try to check again what's wrong. Thank you so much.

[Andrei Bobrov]

Hi Emmanuelle! See ADD in my answer.

[Emmanuelle]

Thanks Andrei, it works! ;)

[Mritula C]

Hi, im facing the same issue. Can you explain what do you mean by " see ADD in my answer" ?

Answer 2

[Steven Lord]

If you're using release R2016b or later you can use the fillmissing function.

[mostafa mahdi yousef]

this is the best answer thanks Steven!

like ypu from IRAN!

Answer 3

[Andrei Bobrov]

eg

data

Data = cell(1,5);
for jj = 1:5
    k = [randi(250,randi([10,15]),1); nan(randi([0 3]),1) ];
    Data{jj} = k(randperm(numel(k)));
end

solution

for jj = 1:numel(Data)
   n = (1:numel(Data{jj}))';
   k = ~isnan(Data{jj});
   Data{jj} = interp1(n(k),Data{jj}(k),n,'linear','extrap');
end

ADD

load doc1.txt
x = doc1(:,1);
y=  doc1(:,2);
t = all(~isnan([x,y]),2);
out = interp1(x(t),y(t),x,'linear','extrap');