Ruby String#tr VS String#gsub benchmark

gistfile1.rb

require 'benchmark'

STRING = 'Haha hah hahaa ahah!!'
FIND = 'a'
REPLACE = 'o'

STRING.tr(FIND, REPLACE) == STRING.gsub(FIND, REPLACE) or abort

Benchmark.bmbm do |bm|
  bm.report '.tr' do
    1_000_000.times { STRING.tr(FIND, REPLACE) }
  end

  bm.report '.gsub' do
    1_000_000.times { STRING.gsub(FIND, REPLACE) }
  end
end

__END__

Rehearsal -----------------------------------------
.tr     0.500000   0.010000   0.510000 (  0.509202)
.gsub   7.230000   0.030000   7.260000 (  7.305856)
-------------------------------- total: 7.770000sec

            user     system      total        real
.tr     0.470000   0.000000   0.470000 (  0.466244)
.gsub   7.110000   0.050000   7.160000 (  7.201910)