How to sort Ruby array with mixed Strings and Fixnums

Question

I need to sort a mixed array in Ruby. It has Fixnum s and String s

ar = [1, "cool", 3, "story", 4, "bro"]

I want the Fixnum s to take precedence over the strings and don't care what order the strings are in.

ar = [1,3,4,"cool","story","bro"]

I've tried writing a method for class Array

Class Array
  def mixed_sort
    self.sort do |a,b|
      if a.class == Fixnum and b.class != a.class
        -1
      else
        a <=> b
      end
    end
  end
end

I thought I might just pass a block to the Array#sort method. However this method still throws an error before hitting the block

[1] pry(main)> [1, "11", '12', 3, "cool"].mixed_sort
ArgumentError: comparison of String with 3 failed
from /config/initializers/extensions/array.rb:3:in `sort'

Answer 1

I would do as below using Enumerable#grep :

ar = [1, "cool", 3, "story", 4, "bro"]
ar.grep(Fixnum).sort + ar.grep(String)
# => [1, 3, 4, "cool", "story", "bro"]

If you want also to sort the strings, do as below :

ar = [1, "cool", 3, "story", 4, "bro"]
ar.grep(Fixnum).sort + ar.grep(String).sort
# => [1, 3, 4, "bro", "cool", "story"]

Answer 2

a, b = [1, "cool", 3, "story", 4, "bro"].partition(&Fixnum.method(:===))
a.sort + b #=> [1, 3, 4, "cool", "story", "bro"]

Answer 3

Practically, I have always needed to sort by Fixnum first and followed by String elements:

ar.sort_by { |n| n.to_s } # => [1, 3, 4, "bro", "cool", "story"]

This only converts an element into string within the block for comparison but returns the Fixnum in it's original state