Sample n times with replacement in Julia
julia, sample
Solution
`wsample(population, weights, n)` returns `n` samples from `population` (not the indexes). This is in the Distributions package.
For example,
julia> using Distributions
julia> wsample(["a", "b"], [0.3, 0.7], 10)
10-element Array{ASCIIString,1}:
"a"
"b"
"b"
"b"
"b"
"b"
"b"
"b"
"a"
"b"
If what you want is to draw indexes, you can use `1:k` as the population, for example, `wsample(1:k, weights, n)`.
Problem
I'm trying to draw n -- say, 10 for simplicity -- samples from an array in Julia. Using the function `wsample`, `ndraws` below gives me what I wanted ``` using Distributions population = [ 1, 10 ] weights = [ .4, .6 ] population_idx = wsample( population, weights, 10 ) # i.e. population indices ndraws = population[ population_idx ] ``` I'm using `Julia 0.2`. Is there a way to do the same thing without the indices? In `R` for instance, we have ``` ndraws <- sample( population, size = 10, replace = TRUE, prob = weights ) ``` The docs here suggests there is i.e. doing this ``` ndraws = wsample( population, weights, 10 ) ``` should give me, err, exactly what I want? Note too, that in the docs, the argument name for number of draws is `n` but looking in the source code of `sample.jl`, it refers to `k`.