[R] na.approx and columns with NA's

[antonio rodriguez]

Hi,

I have a object 'zoo':

dim(zz)
[1]  720 5551

where some columns only have NA's values (representing land data in a 
sea surface temperature dataset) I find straightforward the use of 
'na.approx' for individual columns from the zz matrix, but when applied 
to the whole matrix:

zz.approx<-na.approx(zz)
Erro en approx(along[!na], y[!na], along[na], ...) :
        need at least two non-NA values to interpolate

The message is clear, but how do I could skip those 'full-NA's' columns 
from the interpolation in order to perform the analysis over the columns 
which represent actual data with some NA's values

Best regards,

Antonio

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