To answer my own post, and for the archives (hopefully not that anyone
has to repeat what I had to do ;-), after much hair-pulling , frowning
at the screen and general dumb headedness the following slab of R code
achieves the results I wanted. It isn't elegant but does a job.
msr <- function(x) {
Apologies, Jim Holtman has pointed out a couple of problems/queries with
my original email that I would like to make clear.
Firstly, I introduced a typo when trying to be helpful. In my email
below, I had incorrectly typed out one of the species codes I would
count:
1000
16220602
2011
240
Dear List,
I have a data set stored in the following format:
> head(dat, n = 10)
id sppcode abundance
1 10307 1000 1
2 10307 16220602 2
3 10307 2000 5
4 10307 2011 2
5 10307 2400 1
6 10307 402183
7 10307 40210102
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