Have a function like the "_n_" in R ? (Automatic count function )
On Wed, 25 Feb 2009, Gustaf Rydevik wrote:
On Wed, Feb 25, 2009 at 3:30 PM, hadley wickham <h.wickham at gmail.com> wrote:
And for completeness here's a function that returns the next integer
on each call.
n <- (function(){
?i <- 0
?function() {
? ?i <<- i + 1
? ?i
?}
})()
n()
[1] 1
n()
[1] 2
n()
[1] 3
n()
[1] 4
n()
[1] 5
n()
[1] 6 ;) Hadley
*headache*! I can't wrap my head around this one - too strange code! Could someone please give a hint on what's going on? How does"i<<- i+1" modify i permanently, seeing as i is defined as 0 to start with?
i is not _defined_ as zero. It is initially _assigned_ the value of zero and is subsequently assigned other values. As for the details of what goes here, see An Introduction to R Section 10.7 Scope and study the open.acount() example there. HTH, Chuck
/Gustaf -- Gustaf Rydevik, M.Sci. tel: +46(0)703 051 451 address:Essingetorget 40,112 66 Stockholm, SE skype:gustaf_rydevik
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Charles C. Berry (858) 534-2098
Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu UC San Diego
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