CODEWITHSUNDEEP
rprobability
QZhu
QZhu

Reputation: 7

Assuming a 5 card poker hand what is the probability of having four of a kind? Use R

I know the basic hand calculation is

comb_wo = function(n, x) {
   factorial(n) / factorial(n-x) / factorial(x)
}  
d <- comb_wo(13,1)*comb_wo(4,4)*comb_wo(48,1)/comb_wo(52,5)
d

but if I want to simulation 100 times, and then find out the probability?

Upvotes: 0

Views: 221

Answers (1)

dcarlson
dcarlson

Reputation: 11076

You will have to create a deck of cards, e.g.

Value <- rep(c(2:10, "Jack", "Queen", "King", "Ace"), each=4)
Suit <- rep(c("Clubs", "Diamonds", "Hearts", "Spades"), 13)
Deck <- data.frame(Suit, Value)

Then to create a random hand of 5:

Hand <- Deck[sample.int(52, 5), ]

Do this many times, (100 will not be enough):

set.seed(42) # Just to make this illustration reproducible
Hands <- replicate(10000, Deck[sample.int(52, 5), ], simplify=FALSE)

How many have a four of a kind:

fourkind <- sapply(seq(10000), function(x) any(table(Hands[[x]]$Value) == 4))
sum(fourkind)
#  [1] 1
idx <- which(fourkind)
idx
# [1] 983

If you have a hand(s) with four of a kind:

lapply(idx, function(i) Hands[[i]])
# [[1]]
#        Suit Value
# 10 Diamonds     4
# 12   Spades     4
# 9     Clubs     4
# 41    Clubs Queen
# 11   Hearts     4

Upvotes: 1

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