Dear Cathy,
Try this:
# Some data
set.seed(123)
DF <- data.frame(
Plot=sample(10),
Location = sample(10),
SpeciesName = sample(LETTERS[1:10]),
SpeciesNumber = sample(10),
abundance = rnorm(10),
treatment = sample(letters[1:3],5, replace=TRUE)
)
# Making some NAs in Plot
DF[c(2,7,10),1] <- NA
DF
# Hopefully what you asked for :-)
DF$abundance[is.na(DF$Plot)] <- 0
DF # note than rows 2, 7 and 10 in abundance are now zero
See ?is.na for details.
HTH,
Jorge
On Fri, May 1, 2009 at 1:20 PM, Collins, Cathy <ccoll...@ku.edu> wrote:
> Greetings,
>
> I am new to R and am hoping to get some tips from experienced
> R-programmers.
>
> I have a dataset that I've read into R as a dataframe. There are 5 columns:
> Plot location,species name, a species number code (unique to each species
> name), abundance, and treatment. There are 272 plots in each treatment, but
> only the plots in which the species was recorded have an abundance value.
> For all species in the dataset, I would like to add zeros to the abundance
> column for any plots in which the species was not recorded, so that each
> species has 272 rows. The data are sorted by species and then abundance, so
> all of the zeros can presumably just be tacked on to the last (272-occupied
> plots) row for each species.
>
> My programming skills are still somewhat rudimentary (and biased toward
> VBA-style looping...which seems to be leading me astray). Though I have
> searched, I have not yet seen this particular problem addressed in the help
> files.
>
> Many thanks for any suggestions,
> Cathy
>
> <mailto:ccoll...@ku.edu>
>
>
> ______________________________________________
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
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