If it's not homework, then I'm happy to provide more help:
a <-seq(0,10,by=1)
b <-c(10:20)
d <-data.frame(a=a,b=b)
f <-16
subset(d, b < f & b == max(b[b < f]))$a
# I'd turn it into a function
getVal <- function(d, f) {
subset(d, b < f & b == max(b[b < f]))$a
}
Sarah
On Mon, Dec 9, 2013 at 3:50 PM, Andras Farkas <motyocska at yahoo.com> wrote:
Sarah,
thank you, not homework though, I guess it just looks like it.... I will
look into subset()
Andras
On Monday, December 9, 2013 3:45 PM, Sarah Goslee
<sarah.goslee at gmail.com>
wrote:
Thank you for providing a reproducible example. I tweaked it a little
bit to make it actually a data frame problem.
There are lots of ways to do this; here's one approach.
On second thought, this looks a lot like homework, so perhaps instead
I'll just suggest using subset() with more than one condition.
Sarah
On Mon, Dec 9, 2013 at 3:27 PM, Andras Farkas <motyocska at yahoo.com>
wrote:
Dear All
please help with the following:
I have:
a <-seq(0,10,by=1)
b <-c(10:20)
d <-cbind(a,b)
f <-16
I would like to select the value in column a based on a value in column
b,
where the value in column b is the 1st value that is smaller then f.
Thus I
should end up with the number 5 because the 1st value that is below 16
would
be 15, and in the same row column a has the number 5....
appreciate your insights,
andras