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Ruby Descending Order Method

bighappytrees profile image Aaron Bendersky ・1 min read

Method takes a non-negative integer (n) as an argument then:

  • turns it into a string
  • splits each character in the string into an array of strings
  • sorts the array alphabetically
  • joins the strings together in ascending order
  • reverses the string and turns it back into an integer

Let me know if you found a better way!

def descending_order(n)
  n.to_s.split("").sort_by {|x| x}.join("").reverse.to_i
end

Discussion

markdown guide
 
def descending_order(n)
  n.digits.sort_by { |c| -c.ord }.join.to_i
end

This does a few interesting things:

  • It uses the Integer#digits method, which is effectively the same as int.to_s.chars or int.to_s.split('')
  • It uses the ord method to get the numeric representation of a character, but negates it to get back to an ascending order, much the same as one would do with a numeric list
  • join doesn't require '' as it'll assume that.

Granted there are likely better ways to go about it, but this gives some interesting ideas.