split vs. index

gistfile1.rb

require 'benchmark'

n = 100000
a = nil
b = nil
c = nil

STRING = "foo=bar; domain=example.com; path=/; expires=Sat, 09-Feb-2013 07:27:33 GMT; HttpOnly".freeze

Benchmark.bm do |x|
  x.report do
    n.times do
      a = STRING.split(/\s*;\s*/).first
    end
  end
  x.report do
    n.times do
      b = STRING.split(';').first
    end
  end
  x.report do
    n.times do
      i = STRING.index(';')
      c = STRING[0...i]
    end
  end
end

puts a
puts b
puts c

# user     system      total        real
# 0.810000   0.010000   0.820000 (  0.805447)
# 0.200000   0.000000   0.200000 (  0.207243)
# 0.100000   0.000000   0.100000 (  0.098045)
# foo=bar
# foo=bar
# foo=bar

gistfile2.rb

require 'benchmark'

n = 100000
a = nil
b = nil
c = nil
d = nil

STRING = "foofoofoofoofoofoo=barbarbarbarbarbar; bazbazbazbazbazbaz=quxquxquxquxquxqux; foofoofoofoofoofoo=barbarbarbarbarbar".freeze

Benchmark.bm do |x|
  x.report do
    n.times do
      a = STRING.split(/\s*;\s*/)
    end
  end
  x.report do
    n.times do
      b = STRING.split('; ')
    end
  end
  x.report do
    n.times do
      c = STRING.split(';').map { |s| s.strip }
    end
  end
  x.report do
    n.times do
      str = STRING.dup
      res = []
      while true
        if i = str.index(';')
          res << str[0...i].strip
          str = str[i+1..-1]
        else
          res << str.strip
          break
        end
      end
      d = res
    end
  end
end

puts a.inspect
puts b.inspect
puts c.inspect
puts d.inspect

#        user     system      total        real
#    0.730000   0.010000   0.740000 (  0.729943)
#    0.140000   0.000000   0.140000 (  0.141725)
#    0.350000   0.000000   0.350000 (  0.349824)
#    0.640000   0.000000   0.640000 (  0.646360)
# ["foofoofoofoofoofoo=barbarbarbarbarbar", "bazbazbazbazbazbaz=quxquxquxquxquxqux", "foofoofoofoofoofoo=barbarbarbarbarbar"]
# ["foofoofoofoofoofoo=barbarbarbarbarbar", "bazbazbazbazbazbaz=quxquxquxquxquxqux", "foofoofoofoofoofoo=barbarbarbarbarbar"]
# ["foofoofoofoofoofoo=barbarbarbarbarbar", "bazbazbazbazbazbaz=quxquxquxquxquxqux", "foofoofoofoofoofoo=barbarbarbarbarbar"]
# ["foofoofoofoofoofoo=barbarbarbarbarbar", "bazbazbazbazbazbaz=quxquxquxquxquxqux", "foofoofoofoofoofoo=barbarbarbarbarbar"]