sort.rb

def sort num
  res= []
  res2= []

  arr = num.to_s.split("")
  arr.each { |x| res << x.to_i }
  big_array = res.permutation.to_a
  big_array.each {|x| res2 << x.join.to_i }
  p res2
end

sort(123)

Kirk,

Whenever someone asks me to write a function, I assume they mean I should return a value from that function, and not print out a value. I want to invite you to do the same with me -- return a value, don't print it.

Your solution is otherwise good, but I want to invite you to chain methods together, instead of storing temporary values in local variables.

I also want to invite you to follow the Github Ruby styleguide, which would have you put your arguments in parentheses:

def sort(num)

So altogether, something like this:

def sort(num)
  num.to_s.split("")
  .map{|n| n.to_i}
  .permutation.to_a
  .map{|a| a.join}
end