Again thanks for the input. I've been a recipient of this list for
quite a few years although I don't post often. It is an invaluable
resource and I appreciate the effort of all the contributors. I support
a lot of software so I know how much work it can be.
I've seen the "reproducible code" at the bottom of the messages but
until I got an off-list explanation I had no idea that it meant an
example in which the "code AND data can be copied and pasted directly
into R". I re-read the posting guide and it does suggest providing an
example. Adding a definition for "reproducible code" might help. I've
always interpreted "reproducible" to mean an example that can be used to
"reproduce" the error. However, that is a bit of a catch-22 because in
my case I couldn't reproduce it with a simple example because I didn't
know what to reproduce. I could demonstrate it within my own code. It
didn't make sense until I used str() on the dataframe. Sometimes what
is needed is some insight about what to look for. Now that I
understand the problem, below is the "reproducible code and data"
df=data.frame(x=rep(1,3),y=tapply(1:9,factor(c(rep("A",3),rep("B",3),rep("C",3))),sum))
df
by(df$y,df$x,length)
tapply(df$y,df$x,length)
As suggested table(df$x) would have been the more tidy solution for what
I wanted to do.
regards --jeff
Sebastian P. Luque wrote:
On Tue, 28 Oct 2008 18:04:57 -0700,
Jeff Laake <[EMAIL PROTECTED]> wrote:
Any insight into the behavior of "by" in the following case would be
appreciated. There is a note in the help details for "by" about
documenting behavior since v2.7 but I don't entirely understand what
it is saying. I'm using R2.7.2 Windows. I'm interested if the
following behavior was a change or whether it has always worked this
way. I looked at RSiteSearch and read through version changes but
found nothing.
Take a dataframe as follows:
samples
Region.Label Area Sample.Label Effort Label 1 1 10000 1 100 11 2 1
10000 2 100 12 3 1 10000 3 100 13 4 1 10000 4 100 14 5 1 10000 5 100
15 6 1 10000 6 100 16 7 1 10000 7 100 17 8 1 10000 8 100 18 9 1 10000
9 100 19 10 1 10000 10 100 110
I cannot reproduce your results (please provide reproducible code), but:
table(samples$Region.Label)
is simpler for this purpose.
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