[R] Filling in a series

Gabor Grothendieck ggrothendieck at gmail.com
Sat Oct 21 15:33:08 CEST 2006


Actually I think its last _observation_ carried forward.

On 10/21/06, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
> The zoo package has na.locf (last occurrernce carried foward)
> for this purpose:
>
> > x
>  [1]  1 NA NA NA NA  2 NA NA NA NA  3 NA NA
> > library(zoo)
> > na.locf(x)
>  [1] 1 1 1 1 1 2 2 2 2 2 3 3 3
>
> On 10/21/06, Dennis Fisher <fisher at plessthan.com> wrote:
> > Colleagues
> >
> > After reading in some clinical data, I discovered that the subject ID
> > column contains entries only for the first record for each
> > individual; subsequent rows are recorded as NA.  For example:
> > > 1
> > > NA
> > > NA
> > > NA
> > > NA
> > > 2
> > > NA
> > > NA
> > > NA
> > > NA
> > > 3
> > > NA
> > > NA
> > > ...
> >
> > I can think of various approaches to replace the NA values with
> > appropriate entries.  I could loop through each row - if the value is
> > NA, I replace it with the entry from the row above.  Or, I could find
> > the positions of the non-NA values with match, then replace groups of
> > entries (e.g., positions 2-5) with appropriate entries, again with a
> > loop.
> >
> > But, I expect that R allows some more clever approach to the
> > problem.  Any thoughts?
> >
> > Dennis
> >
> > Dennis Fisher MD
> > P < (The "P Less Than" Company)
> > Phone: 1-866-PLessThan (1-866-753-7784)
> > Fax: 1-415-564-2220
> > www.PLessThan.com
> >
> >
> >        [[alternative HTML version deleted]]
> >
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> >
>



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