[R] Performance note: Preallocating helps? and two questions

[Bob Sandefur]

hi-
 in r 1.1 on windows 2000
 with length(AU) of 35833
 AUcap30<-0
 for(i in 1:length(AU))AUcap30[i]<-min(30,AU[i]) 
took over an hour on pentium II 300 mhertz (I esc'ed before it finished)
but
AUcap30<-AU 
 for(i in 1:length(AU))AUcap30[i]<-min(30,AU[i]) 
is very quick (a few seconds)

Is this performance difference common in r (ie is linux the same way)?

Are there other tricks to speed up R (in windows) (besides a faster processor and more memory)?

thanx

bob sandefur

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