[R] summation sign
peter dalgaard
pdalgd at gmail.com
Sat Oct 27 09:13:56 CEST 2012
On Oct 27, 2012, at 01:34 , sffarooqi wrote:
> Hi all,
> I have a very quick question on how to use the summation sign in R for the
> function.
> Here´s a basic example: the function is sum(i=1 to 5)log(1-xi^2)
> Id be grateful if someone knows how to do this without writing it out 5
> times - I am looking sth along the lines of the following:
>
> computeR <- function(x)
> {
> return (-sum(log(1-x^2))
> }^
> thank you vm in advance!
You pretty much did it already:
> x <- c(.5,.6,.7,.4,.8)
> -sum(log(1-x^2))
[1] 2.603318
I.e., just have x as a vector of length 5 and the rest is done automagically.
(And, BTW, you don't need return() in a function like that in R, the return value is the value of the last expression.)
--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com
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