Version sort (with alphas, betas, etc.) in ruby

Question

How do I sort a list of versions in Ruby? I've seen stuff about natural sort, but this is a step beyond that.

Input is a bunch of strings like this:

input = ['10.0.0b12', '10.0.0b3', '10.0.0a2', '9.0.10', '9.0.3']

I can almost do it with the naturally gem:

require 'naturally'
Naturally.sort(input)
=> ["9.0.3", "9.0.10", "10.0.0a2", "10.0.0b12", "10.0.0b3"]    

Problem: 10.0.0b3 is sorted after 10.0.0b12; 10.0.0b3 should be first.

Anyone have a way that works? Other languages are helpful too!

Answer 1

Ruby ships with the Gem class, which knows about versions:

ar = ['10.0.0b12', '10.0.0b3', '10.0.0a2', '9.0.10', '9.0.3']

p ar.sort_by { |v| Gem::Version.new(v) }
# => ["9.0.3", "9.0.10", "10.0.0a2", "10.0.0b3", "10.0.0b12"]

Answer 2

If you interpret this as "sort by each segment of digits", then you the following will handle your example input above:

input.map{ |ver| ver.split(%r{[^\d]+}).map(&:to_i) }.zip(input).sort.map(&:last)
=> ["9_0", "9_1", "10_0b3", "10_0b12"]

That is,

• for each value, eg 10_0b3
• split on any length of non-digit characters, eg ["10","0","3"]
• cast each digit segment to integer, eg [10,0,3]
• zip with original input, yields [[[10, 0, 12], "10_0b12"], [[10, 0, 3], "10_0b3"], [[9, 0], "9_0"], [[9, 1], "9_1"]]
• sort, by virtue of [10,0,3] < [10,0,12]
• get last value of each element, which is the original input value which corresponds to each processed sortable value

Now granted, this is still quite custom -- version numbers as simple as "9_0a" vs "9_0b" won't be handled, both will appear to be [9,0] -- so you may need to tweak it further, but hopefully this starts you down a viable path.

EDIT: Example input above changed, so I changed the regex to make sure the digit-matching is greedy, and with that it still holds up:

irb(main):018:0> input = ['10.0.0b12', '10.0.0b3', '9.0.10', '9.0.3']
=> ["10.0.0b12", "10.0.0b3", "9.0.10", "9.0.3"]
irb(main):025:0> input.map{ |ver| ver.split(%r{[^\d]+}).map(&:to_i) }.zip(input).sort.map(&:last)
=> ["9.0.3", "9.0.10", "10.0.0b3", "10.0.0b12"]