[R] Automatic routine - NEW
Monica Palaseanu-Lovejoy
monica.palaseanu-lovejoy at stud.man.ac.uk
Wed Jun 23 14:53:27 CEST 2004
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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