avoiding the sample in built function
On Nov 23, 2011, at 2:56 PM, Kevin E. Thorpe wrote:
On 11/23/2011 02:01 PM, sarah44 wrote:
Dear all, I am currently working on a function in which I would like to avoid using the command sample(). Therefore, I am now trying to make a for loop that does the same thing as the in built function sample does: Rearranging the items of a object randomly. So, the output I want to you get is the same as sample() would give me: e.g.: data<- c(5,4,6,7,8) sample(data)
data<- c(5,4,6,7,8) sample(data)
[1] 4 6 7 8 5
sample(data)
[1] 6 8 4 7 5
sample(data)
[1] 6 5 4 8 7
Herefore I made a for loop which you can see here:
This for loop is supposed to do the same as the sample() function,
3 times.
data<- c(5,4,6,7,8)
numsim<- 3
n<- length(data)
sample<- matrix(0,numsim,1)
for (i in 1:numsim) {indices<- runif(pool, min = 1, max = n)
sample[i,]<- data[indices]
}
the idea behind this for loop is dat it first creates randomly data
by
runif, and then it should
somehow, by using indeces, store this 3 times in a matrix 'sample'.
Somehow, I am stuck here and I think that the sample[,i] part is
just very
wrong. I am however
not for a very long time an R user, so I cannot find the solution
to this
problem.
Can someone give me a hint?
Thanks very much!
Bye, sarah
The only reason I can think of you wanting to avoid sample() is because this is homework and the list is not for homework. If I have misjudged the intent of your post, please forgive me.
Furthermore a similar question was already asked and answered on the list recently, so it appears to be a common programming exercise. (My response to that one was to offer a hint but the questioner didn't quite get it so it took a couple of days for the answer to apper.) Perhaps the real test is to see if one knows how to search?
David Winsemius, MD West Hartford, CT