MATLAB: Fill in missing NaNs

fillingnan

I am trying to fill these NaNs following this rule: If there is a single NAN, I want the NAN to be filled in with the average of the numbers before and after. If there is more than one NAN. I want the NAN to be filled in with the nearest number. For example, row 2305 should be the average of 16.3 and 14.8, from 2298 to 2304 should be 16.3, and from 2306 to 2312 should be 14.8.

Best Answer

Try this:
x = [1;2;3;4;nan;nan;nan;nan;nan;5;7;8;nan;nan;nan;nan;11;11;12;nan;nan;nan;15];
bb = regionprops(isnan(x));
idx_nnan = find(~isnan(x));
idx_nan = find(isnan(x));
[~,idx] = min(abs(idx_nan - idx_nnan'), [], 2);
x(idx_nan) = x(idx_nnan(idx));
a = [bb.Centroid];
a(1:2:end) = [];
bb = bb(a==fix(a));
for i=1:numel(bb)
    idx_center = bb(i).Centroid(2);
    idx = cumsum(bb(i).BoundingBox([2 4])) + [-0.5 0.5];
    x(idx_center) = mean(x(idx));
end
Original x:
x =
     1
     2
     3
     4
   NaN
   NaN
   NaN
   NaN
   NaN
     5
     7
     8
   NaN
   NaN
   NaN
   NaN
    11
    11
    12
   NaN
   NaN
   NaN
    15
New x:
x =
    1.0000
    2.0000
    3.0000
    4.0000
    4.0000 % <--- nearesr value








    4.0000 % <--- nearesr value
    4.5000 % average

    5.0000 % <--- nearesr value
    5.0000 % <--- nearesr value
    5.0000
    7.0000
    8.0000
    8.0000 % <--- nearesr value
    8.0000 % <--- nearesr value
   11.0000 % <--- nearesr value 
   11.0000 % <--- nearesr value
   11.0000
   11.0000
   12.0000
   12.0000 % <--- nearesr value
   13.5000 % average
   15.0000 % <--- nearesr value
   15.0000
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