[R] [Q] Setting elements of a vector
Uwe Ligges
ligges at statistik.uni-dortmund.de
Mon Nov 12 22:17:20 CET 2001
Stefan Meyer wrote:
>
> Hi!
>
> I'm new to R and have problems with the following code:
>
> <code>
>
> awprob<-c(0.4,0.4,0.1,0.1)
> awsample<-sample(c(1:4),3,awprob,replace=TRUE)
>
> vec<-vector(mode="numeric",10000)
> vec[]<-sum(sample(c(1:4),20,awprob,replace=TRUE))
>
> </code>
>
> My problem: The elements of vec have the same value. How
> can I tell R that I want to have a *new* sample for each value
> and not 10000 times the same sample?
I don't really understand what you are going to do, but vectorizing the
last statement correctly should result in something like:
awprob <- c(0.4, 0.4, 0.1, 0.1)
# Matrix with 20 * 10000 samples (20 columns, 1000 rows):
X <- matrix(sample(c(1:4), 200000, awprob, replace=TRUE), ncol=20)
# Now applying for each row the sum():
vec <- apply(X, 1, sum)
> A for-loop is not a good solution as it made R hang up ...
No, it won't hang up! But for such a data set a for loop is very slow.
Just wait a few minutes - or don't use for()!
Uwe Ligges
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
More information about the R-help
mailing list