Hi,
I am enjoying myself with the famous Birthday paradox, looking at the probability of several persons (36 in this case) having their birthday the same day. I've managed to come so far:

# a vector for the number of days in a year

yeardays <- seq(1:365)

# A vector for the number of repeated samplings (100)

B <- 100

# A matrix with 100 columns and 36 rows from 100 repeated samplings with 36 random samples each

S <- replicate(B, {
X <- sample(yeardays, 36, replace = TRUE)
})

# Sum the number of duplicates in one column

sum(duplicated(S[,1]))

Now, what I don't get is how to get the sum of duplicates for each of the 100 columns. A loop or perhaps "apply" should do it, but I just don't get the output of 100 sums I would need. Any clue would be so great! Thanks!