On 2010-11-28 19:38, Joshua Wiley wrote:
Hi Eric,
I think this does what you want. It may be a simple question, but
that does not necessarily mean the easiest/fastest answer is
intuitive. Welcome to R!
dat<- data.frame(v = 1:100)
## the with() is just a convenient way to avoid having to type
## dat$v every single time---similar to attach(), but cleaner
## the idea is to create three vectors, that are offset by removing
## either the first observation or the last
with(dat, (v[-1] - v[-length(v)])/v[-length(v)])
HTH,
Josh
That's a good first-time user solution.
Then, since this is R, here's the next step:
v <- sample(50, 100, replace = TRUE)
result <- diff(v) / v[-length(v)]
Peter Ehlers
On Sun, Nov 28, 2010 at 7:29 PM, eric<ericst...@aol.com> wrote:
Just starting to learn R so excuse me if this is a simple question. I'm
wondering how I get the percent difference in sequential values in one
column of a dataframe. If I had a dataframe and one of the columns was
"value", how would I go about calculating (v2-v1)/v1 ....(v3-v2)/v2
....(v4-v3)/v3 ...etc ?
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