Monte-Carlo simulation of the five cards

poker.R

drawfive <- function(iter){
  three = 0L
  four = 0L
  onepair = 0L
  twopair = 0L
  fullhouse = 0L
  straight = 0L
  flush = 0L
  #iter <- 100000
  dec <- expand.grid(suit=1L:4L,rank=1L:13L)
  for(i in 1:iter){
    ind <- sort(sample.int(52L, size = 5))
    hand <- dec[ind,]
    flush = flush + as.integer(any(table(hand$suit)==5L))
    straight =  straight + as.integer(all(diff(sort(hand$rank))==1L))
    tabr <- table(hand$rank)
    fullhouse = fullhouse + as.integer(any(tabr==2L)&any(tabr==3L))
    four = four + as.integer(any(tabr==4L))
    three = three + as.integer(any(tabr==3L))
    onepair = onepair + as.integer(any(tabr==2L)) 
    twopair = twopair + as.integer(sum(tabr==2L)==2L)  
  }
  c(straight = straight,
    flush = flush,
    fullhouse = fullhouse,
    four=four,
    three=three,
    twopair=twopair,
    onepair=onepair)/iter
}
set.seed(12345)
system.time({
  res <- drawfive(100000)  
})
round(res, 3)