[R] Automatic routine - NEW
Liaw, Andy
andy_liaw at merck.com
Wed Jun 23 15:09:03 CEST 2004
Sounds to me that you are looking for something like:
subDF <- DF[3:5,]
Andy
> From: Monica Palaseanu-Lovejoy
>
> Hi Again,
>
> First of all thank you for all the responses to my previous query.
> Your answers were very helpful and I did the job ;-). Now I hope you
> can answer as quick the following (sorry I am invading you with
> trivial questions):
>
> Let's use again the following data.frame example:
> DF <- data.frame(x=rnorm(5), y=rnorm(5))
>
> I want to obtain a new data.frame (or matrix) that contains only n
> rows (from the i rows DF has), and all the columns. If I have
> to do it
> step by step I would do something like that, for example:
>
> a3 <- DF[3,]
> a4 <- DF[4,]
> a5 <- DF[5,]
> b <- data.frame(a3, a4, a5)
> c <- matrix(b, nrow=3, ncol=2, byrow=TRUE)
>
> Now I want to do the same in one go, so I wrote:
>
> for (i in 3:5)
> {
> d[i] <- DF[i,]
> e <- data.frame(d[i])
> f <- matrix(e, ncol=2, nrow=3, byrow=TRUE)
> }
>
> Which of course gives me errors and the matrix f has all elements
> equal with DF[5,5]. If I don't use [i] after d, the resulting
> f matrix is
> made up from the DF[5,] elements (which is quite normal since i
> replaces itself ...). So .... How is this done correctly?
>
> I am really appreciating your time and effort to answer me,
>
> Monica
>
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