How to compare versions in Ruby?
RubyRuby Problem Overview
How to write a piece of code to compare some versions strings and get the newest?
For example strings like: '0.1', '0.2.1', '0.44'.
Ruby Solutions
Solution 1 - Ruby
Gem::Version.new('0.4.1') > Gem::Version.new('0.10.1')
Solution 2 - Ruby
If you need to check pessimistic version constraints, you can use Gem::Dependency like this:
Gem::Dependency.new('', '~> 1.4.5').match?('', '1.4.6beta4')
Solution 3 - Ruby
class Version < Array
def initialize s
super(s.split('.').map { |e| e.to_i })
end
def < x
(self <=> x) < 0
end
def > x
(self <=> x) > 0
end
def == x
(self <=> x) == 0
end
end
p [Version.new('1.2') < Version.new('1.2.1')]
p [Version.new('1.2') < Version.new('1.10.1')]
Solution 4 - Ruby
You can use the Versionomy gem (available at github):
require 'versionomy'
v1 = Versionomy.parse('0.1')
v2 = Versionomy.parse('0.2.1')
v3 = Versionomy.parse('0.44')
v1 < v2 # => true
v2 < v3 # => true
v1 > v2 # => false
v2 > v3 # => false
Solution 5 - Ruby
I would do
a1 = v1.split('.').map{|s|s.to_i}
a2 = v2.split('.').map{|s|s.to_i}
Then you can do
a1 <=> a2
(and probably all the other "usual" comparisons).
...and if you want a < or > test, you can do e.g.
(a1 <=> a2) < 0
or do some more function wrapping if you're so inclined.
Solution 6 - Ruby
Gem::Version is the easy way to go here:
%w<0.1 0.2.1 0.44>.map {|v| Gem::Version.new v}.max.to_s
=> "0.44"
Solution 7 - Ruby
If you want to do it by hand without using any gems, something like the following should work, though it's a little perly looking.
versions = [ '0.10', '0.2.1', '0.4' ]
versions.map{ |v| (v.split '.').collect(&:to_i) }.max.join '.'
Essentially, you turn each version string in to an array of integers and then use the http://ruby-doc.org/core/classes/Array.html#M002204">array comparison operator. You could break out the component steps to get something a little easier to follow if this is going in code somebody will need to maintain.
Solution 8 - Ruby
I had the same problem, I wanted a Gem-less version comparator, came up with this:
def compare_versions(versionString1,versionString2)
v1 = versionString1.split('.').collect(&:to_i)
v2 = versionString2.split('.').collect(&:to_i)
#pad with zeroes so they're the same length
while v1.length < v2.length
v1.push(0)
end
while v2.length < v1.length
v2.push(0)
end
for pair in v1.zip(v2)
diff = pair[0] - pair[1]
return diff if diff != 0
end
return 0
end