Filling incomplete data with cftool

Hello, I've been working with data obtained from body signals, but some data values are NaN so the curve has voids in it, I tried to aproximate the curve with cftool, but I don't know how to fix the data matrix and replace the NaN values. I need to keep the same number of data in the matrix.

Answer 1

[William Rose]

@Nicolas Silva Schmalbach

See attached.

%replaceNaNs.m   WCRose 20210928
%Replace NaN values in array with interpolated values.
clear;
%Create simulated data
t=0:.001:1;
x=cos(10*pi*t);
%Add NaNs to the data
for i=1:length(x)
    if rand<.3, x(i)=NaN; end
end
fprintf('NaNs in x(): %d out of %d\n',sum(isnan(x)),length(x));

NaNs in x(): 294 out of 1001

%Fix it by interpolation
%1. Determine how many consecutive NaNs at start of array
k1=0;
while isnan(x(k1+1)),k1=k1+1; end
%2. Determine how many consecutive NaNs at end of array
k2=0;
while isnan(x(end-k2)), k2=k2+1; end
%3. Remove beginning and/or end, if they are NaNs.
y=x(1+k1:end-k2);
%4. Replace remaining NaNs by linear interpolation
i=1;
while i<length(y)
    if isnan(y(i))
        j=1;
        while isnan(y(i+j)), j=j+1; end
        %Now we know we have j consecutive NaNs, starting at y(i)
        %Replace the NaNs by linear interpolation
        y(i:i+j-1)=y(i-1)+(1:j)*(y(i+j)-y(i-1))/(j+1);
        i=i+j+1;
    else
        i=i+1;
    end
end
fprintf('NaNs in y(): %d out of %d\n',sum(isnan(y)),length(y));

NaNs in y(): 0 out of 997

%5. Plot results
figure;
subplot(2,1,1)
plot(t,x,'.b')
subplot(2,1,2)
plot(t(1+k1:end-k2),y,'.r')

Answer 2

[Steven Lord]

Do you want to remove the NaN values with rmmissing, fill them using fillmissing, or do something else with them (and if so what?)