Replacing NaN with the average of previous and next cell value

I have a data set like,

time 1 2 3 4 5 6 7 8 
exp1 45 67 78 NaN 80 81 82 83

These are two separate column with time and exp1 as header. how do I replace the NaN with the average of previous cell value and the next. Like in the above example, NaN should be replaced by 79 ((78+80)/2 )

Thanks in advance

[Paolo]

When you say header, do you mean you are you working with a table?

[Jan]

Please post the input data in valid Matlab syntax. A "data set" might be a variety of things.

[Paolo]

Also, can there be multiple NaNs?

Answer 1

[Razvan Carbunescu]

This sounds like a use for fillmissing with linear option:

>> exp1 = [45 67 78 NaN 80 81 82 83];
>> fillmissing(exp1,'linear')

ans =

      45    67    78    79    80    81    82    83

[krai]

It works as required. Thanks

[Jan]

+1. Yes, fillmissing is better than fillgaps.

Answer 2

[Jan]

Maybe:

y = fillgaps(exp1, 3, 1)
% Needs Matlab >= R2016a

[EDITED] Sorry, this does not do, what I expect. 
According to the documentation I'd expect a linear fit to the neighboring
elements.

Or:

valid     = ~isnan(exp1);
y         = exp1;
y(~valid) = interp1(time(valid), exp1(valid), time(~valid))

This is a linear interpolation.

Answer 3

[Paolo]

If you are working with a table:

 %Table.
 var = {'time';'exp1'};
 time = [1;2;3;4;5;6;7;8];
 exp1 = [45;67;78;NaN;80;81;82;83];
 t = table(time,exp1);
 x = t.exp1;

 nan = isnan(x);
 indx = find(nan);
 x(nan) = (x(indx-1)+x(indx+1))/2;
 t.exp1 = x;

If you are working with a cell array:

 %Cell array.
 var = {'time',1,2,3,4,5,6,7,8;'exp1',45,67,78,NaN,80,81,82,83};
 x = cell2mat(var(2,2:end));

 nan = isnan(x);
 indx = find(nan);
 x(nan) = (x(indx-1)+x(indx+1))/2;
 var(2,2:end) = num2cell(x);