[R] avoiding the sample in built function

R. Michael Weylandt michael.weylandt at gmail.com
Wed Nov 23 20:52:57 CET 2011


Why would you want to avoid sample()? It's a perfectly wonderful function.

Michael

On Wed, Nov 23, 2011 at 2:01 PM, sarah44 <flokke at live.de> 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
>
> --
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>
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