[R] Sampling

[Chuck Cleland]

On 2/5/2008 1:52 PM, Judith Flores wrote:
> Hi there,
> 
>    I want to generate different samples using the
> followindg code:
> 
> 
> g<-sample(LETTERS[1:2], 24, replace=T)
> 
>    How can I specify that I need 12 "A"s and 12 "B"s?
> 
> Thank you,
> 
> Judith

x <- rep(c("A","B"), each=12)

x
  [1] "A" "A" "A" "A" "A" "A" "A" "A" "A" "A" "A"
[12] "A" "B" "B" "B" "B" "B" "B" "B" "B" "B" "B"
[23] "B" "B"

# "sample(x) generates a random permutation of the elements of x"

g <- sample(x)

g
  [1] "A" "A" "B" "A" "B" "B" "B" "B" "A" "B" "A"
[12] "A" "B" "A" "A" "A" "B" "B" "B" "A" "A" "B"
[23] "A" "B"

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-- 
Chuck Cleland, Ph.D.
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