[R] count the # of appearances...

[Chuck Cleland]

bunny , lautloscrew.com wrote:
> Hi there,
> 
> is there a possibility to count the number of appearances of an  
> element in a vector ?
> i mean of any given element.. deliver all elements which are exactly  
> xtimes in this vector ?
> 
> thx in advance !!

> myvec <- c(0, rep(1:6, each = 2), 7, 7, 7)

> table(myvec)
myvec
0 1 2 3 4 5 6 7
1 2 2 2 2 2 2 3

# Extract elements appearing twice

> myvec[myvec %in% names(which(table(myvec) == 2))]
 [1] 1 1 2 2 3 3 4 4 5 5 6 6

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-- 
Chuck Cleland, Ph.D.
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