On Thu, 2 Jan 2003, Tord Snall wrote:
> I have a tree data matrix.
Don't think so: you appear to have a data frame, which is not at all the
same thing.
> For some trees I lack info about tree species,
> but I want to set them to be spruce. For some reason the tree species names
> on the remaining (non-NA) rows are changed into numbers (that I do not
> recognise).
You should do so. They are the code of the factor in your data frame.
> I guess that ifelse is not the correct function to use, but I have not
> found any better one in my searches.
Your two arguments to ifelse are a character vector and a factor. You
will get coercion of the factor to an atomic type, and that's where the
codes come from.
test$tree.sp[is.na(test$tree.sp)] <- "spruce"
is probably what you wanted.
>
> Thanks in advance!
>
> Sincerely,
> Tord
>
>
> > test
> ObjektID tree.sp Diameter
> 2030 S.2001.S5 <NA> 2
> 2034 S.2001.S5 <NA> 2
> 1 S.1 spruce 2
> 2 S.1 birch 12
> 3 S.1 spruce 7
> 4 S.1 spruce 5
> 5 S.1 birch 8
>
> > test$tree.sp6<- ifelse(is.na(test$tree.sp) == T,
"spruce", test$tree.sp)
>
> > test
> ObjektID tree.sp Diameter tree.sp6
> 2030 S.2001.S5 <NA> 2 spruce
> 2034 S.2001.S5 <NA> 2 spruce
> 1 S.1 spruce 2 8
> 2 S.1 birch 12 3
> 3 S.1 spruce 7 8
> 4 S.1 spruce 5 8
> 5 S.1 birch 8 3
>
>
> -----------------------------------------------------------------------
> Tord Snäll
> Avd. f växtekologi, Evolutionsbiologiskt centrum, Uppsala universitet
> Dept. of Plant Ecology, Evolutionary Biology Centre, Uppsala University
> Villavägen 14
> SE-752 36 Uppsala, Sweden
> Tel: 018-471 28 82 (int +46 18 471 28 82) (work)
> Tel: 018-25 71 33 (int +46 18 25 71 33) (home)
> Fax: 018-55 34 19 (int +46 18 55 34 19) (work)
> E-mail: Tord.Snall at ebc.uu.se
> Check this: http://www.vaxtbio.uu.se/resfold/snall.htm!
> ------------------------------------------------------------------------
>
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--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
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