On Jul 30, 2011, at 5:13 AM, Dennis Murphy wrote:
Hi:
Try this:
set.seed(266)
dfm <- data.frame(c1 = sample(1:5, 10, replace = TRUE),
e1 = sample(1:3, 10, replace = TRUE),
c2 = sample(1:5, 10, replace = TRUE),
e2 = sample(1:3, 10, replace = TRUE),
c3 = sample(1:5, 10, replace = TRUE),
x = 1:10)
f <- function(d) with(d, c1^e1 + c2 * x^e2 + c3)
f(dfm)
[1] 70 6 172 86 15 173 254 158 19 505
If there were multiple species (and we cannot tell in the absence of a
reproducible example) you may need to add a match() operation to
select the proper row of coefficients and exponents in "dfm" on the
basis of the species value in each line of input of x.
--
David.
HTH,
Dennis
On Sat, Jul 30, 2011 at 1:06 AM, Benjamin Caldwell
<btcaldw...@berkeley.edu> wrote:
Hello,
I'm just trying to wrap my head around the syntax for creating loops,
functions in R. I have an array of values from a .csv. Looks
something like
header<-c(species,coefficient1, exponent1, coefficient2, exponent2,
constant)
with a species name for the first column, and values for
coefficient1,
exponent1, coefficient2, exponent2, constant for each species.
The values are parameters for an equation
V<-((coefficient1*(x)^exponent1)+
(coefficient2*(x)^exponent2)+constant)
x<1:100
I'd like to run the equation using the parameters for each species
and the
vector x to simulate what V would be for the range of values x, and
then
plot a graph of for each species.
Would the way to do this be some sort of apply nested within a for
loop?
Code so far looks like
vol<-read.csv("frame.csv")
vol.exp<-function(coefficient1, exponent1, coefficient2, exponent2,
constant,x) {
V<-((coefficient1*(x)^exponent1)+
(coefficient2*(x)^exponent2)+constant)
V
}
x<1:100
Thanks
*Ben *
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______________________________________________
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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.
David Winsemius, MD
West Hartford, CT
______________________________________________
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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.
