sample a population based on variable according to a parametric distribution

gistfile1.md

Imagine having a population where age of individuals is known. I would like to sample from this population individuals by age according to a parametric distribution (e.g. X ~ Poisson(1.82)). In other words, I would like to remove a known number of individuals from each class, where class sizes follows a Poisson distribution.

Is there a more elegant way?

ma <- 10 # max age
ss <- 50 # sample size
l <- 1.82 # lambda in Poisson distribution

set.seed(357)
# let's say we have a population of animals of ages
ages <- sample(x = 0:ma, size = 1000, replace = TRUE)
# we want to remove ss number of individuals according to
# X ~ Poisson(l)
cull.by.age.class <- table(rpois(n = ss, lambda = l))

before.removal <- table(ages)

# for each class, sample perscribed number of individuals
# and remove them from the population
for (i in seq_along(cull.by.age.class)) {
  find.inds <- which(ages %in% as.numeric(names(cull.by.age.class[i])))
  num.to.remove <- cull.by.age.class[i]
  to.remove <- sample(
    # find individuals of age i
    find.inds,
    # sample given number of individuals
    num.to.remove
  )
  ages[to.remove] <- NA
}

after.removal <- table(ages)
removal <- cbind(before.removal, after.removal)
removal <- cbind(removal, n_removed = -apply(removal, MARGIN = 1, FUN = diff))
removal

   before.removal after.removal n_removed
0             106            99         7
1              78            63        15
2              87            75        12
3              83            76         7
4              95            90         5
5              89            86         3
6             102           101         1
7             101           101         0
8              75            75         0
9              92            92         0
10             92            92         0