Problem Statement

The   population count   is the number of   1s   (ones)   in the binary representation of a non-negative integer. Population count   is also known as:

For example,   5   (which is   101   in binary)   has a population count of   2.

Evil numbers   are non-negative integers that have an   even   population count. Odious numbers     are  positive integers that have an    odd   population count.

Let's start with the solution:

func population_count(n) { n.as_bin.count('1') }
say "#{0..29 «**« 3 «call« population_count -> join(' ')}"
 
var numbers = 60.of { |i|
    [i, population_count(i)]
}
 
say "Evil:   #{numbers.grep{_[1] %% 2}.map{.first}.join(' ')}"
say "Odious: #{numbers.grep{_[1] &  1}.map{.first}.join(' ')}"