bench.rb

# -*- coding:utf-8 -*-
require 'benchmark'

def gsub_check
  10000.times do |n|
    "　".gsub(/　/, " ")
  end
end

def gsub_check_2
  10000.times do |n|
    "　".gsub!(/　/, " ")
  end
end

def tr_check
  10000.times do |n|
    "　".tr("　", " ")
  end
end

Benchmark.bm(100) do |x|
  x.report("gsub") { gsub_check }
  x.report("gsub!") { gsub_check_2 }
  x.report("tr") { tr_check }
end