wrandom

Ruby weighted random

Installation

gem install wrandom

Usage

# wsample => obj
# wsample(random: rng) => obj
# wsample(n) => new_ary
# wsample(n, random: rng) => new_ary
# wshuffle => new_ary
# wshuffle(random: rng) => new_ary
# wshuffle! => ary
# wshuffle!(random: rng) => ary
arr = [1, 2, 3]
# Choose a weighted random element from the array.
arr.wsample { |v| v * 10 }  #=> 3
# Choose n weighted random elements from the array.
arr.wsample(2) { |v| v * 10 }  #=> [3, 2]
# Choose n weighted random elements from the array.
arr.wsample(2, random: Random.new) { |v| v * 10 }  #=> [3, 2]
# Returns a new array with shuffled by weight.
arr.wshuffle { |v| v * 10 }  #=> [3, 2, 1]
arr #=> [1, 2, 3]
# Shuffles elements by weight.
arr.wshuffle! { |v| v * 10 }  #=> [3, 2, 1]
arr #=> [3, 2, 1]

# [1,9].sample
Hash[100_000.times.map { [1,9].sample            }.group_by(&:to_i).map { |k,v| [k, (v.size.to_f / 1000)]}]
#=> {1=>50.111, 9=>49.889}
# [1,9].wsample { |v| 1 }
Hash[100_000.times.map { [1,9].wsample { |v| 1 } }.group_by(&:to_i).map { |k,v| [k, (v.size.to_f / 1000)]}]
#=> {1=>50.111, 9=>49.889}
# [1,9].wsample { |v| v }
Hash[100_000.times.map { [1,9].wsample { |v| v } }.group_by(&:to_i).map { |k,v| [k, (v.size.to_f / 1000)]}]
#=> {9=>89.887, 1=>10.113}

License

The MIT License (MIT)