Replace NaN's in NumPy array with closest non-NaN value

Question

I have a NumPy array a like the following:

>>> str(a)
\'[        nan         nan         nan  1.44955726  1.44628034  1.44409573\\n  1.4408         


        

Answer 1

I want to replace each NaN with the closest non-NaN value... there will be no NaN's in the middle of the numbers

The following will do it:

ind = np.where(~np.isnan(a))[0]
first, last = ind[0], ind[-1]
a[:first] = a[first]
a[last + 1:] = a[last]

This is a straight numpy solution requiring no Python loops, no recursion, no list comprehensions etc.