Re: [R] any alternatives for complex for-loops?

From: Kinoko <andzsinszan_at_gmail.com>
Date: Tue, 11 Nov 2008 21:48:11 -0800 (PST)

Thanks for the replies

Sorry for being unclear.

I am asking if there is a way to process a vector in a way that uses references to other elements of the same vector. And doing this without a for-loop.

Here is a running code:

<code>

complexFn <- function(a,b){
  c <- (a+b)/2
  return(c)
}

x <- 1:10
y <- rep(NA, length(x))

for (i in 1:length(x)){

    if(i>1){

        y[i] = complexFn(x[i-1], x[i])
    }
}
print(y)
</code>

And here is another attempt without the for-loop.

<code>

x <- 1:10
x1 <- c(NA, x)
length(x1)<-length(x)

y<-mapply(complexFn,x,x1)
print(c(y))
</code>

If someone could tell me the normal/elegant/effective/R way of doing this kind of vector processing, that would highly appreciated.

best,

gabor



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