From: Mikael Brockman <mikael@...>
Date: 2004-09-23T20:03:13+09:00
Subject: Re: whitespace string only

"trans.  (T. Onoma)" <transami@runbox.com> writes:

> So which method is fastest?
> 
> Considering how common this can be, one would think it were a built-in String 
> method (encoded in c) already.
> 
> T.

$ ruby whitespace.rb 
      user     system      total        real
henrik  0.860000   0.110000   0.970000 (  0.977667)
evan    8.240000   2.220000  10.460000 ( 10.524390)
mikael  0.010000   0.000000   0.010000 (  0.014141)
tonoma  0.040000   0.000000   0.040000 (  0.041485)

Here's the benchmark:

| require 'benchmark'
| 
| n = 50
| 
| $whitespace = "                        \n" * 1000
| 
| $nonwhitespace = $whitespace
| $nonwhitespace[-2] = 'a'
| 
| class String
|   def henrik
|     strings_to_test = split("\n")
|     whitespace = /^\s+$/
|     is_whitespace_only = true
|     strings_to_test.each{ |str|
|       unless whitespace.match(str) or str.empty?
|         is_whitespace_only = false
| 	break
|       end	
|     }
|     is_whitespace_only
|   end
| 
|   def evan
|     each_byte { |b| return false unless [9,10,32].include?(b) }
|     true
|   end
| 
|   def mikael
|     self !~ /[^\s]/
|   end
| 
|   def tonoma
|     strip.length == 0
|   end
| end
| 
| Benchmark::bm do |x|
|   test_algorithm = lambda do |id|
|     x.report id.to_s do
|       whitespace_tester = $whitespace.method id
|       nonwhitespace_tester = $nonwhitespace.method id
|       n.times { whitespace_tester.call }
|       n.times { nonwhitespace_tester.call }
|     end
|   end
|   
|   test_algorithm.call :henrik
|   test_algorithm.call :evan
|   test_algorithm.call :mikael
|   test_algorithm.call :tonoma
| end