From: Srinivas JONNALAGADDA <srinivas.j@...>
Date: 2006-09-15T22:32:22+09:00
Subject: Re: Benchmark for Ruby

On Fri, 2006-09-15 at 21:43 +0900, Francis Cianfrocca wrote:
> Some of the surprises: Symbol#=== is really slow. Replace case statements
> against Symbols with if/then constructions.

I have a lot of requirement of the kind shown below, where ':asdf' would
be passed in as a parameter. I have written trivial versions of both
'case' and 'if/elsif/else'. The difference is very little, even over 10
million comparisons. But, in fact, 'case' seems to be faster.

js@srinivasj:~> cat tmp/test/1.rb
def timer
  b = Time.now
  yield
  e = Time.now
  puts "Time taken is #{e - b} seconds."
end

timer do
  10_000_000.times do | __ |
    x = case :asdf
        when :a
          'a'
        when :b
          'b'
        when :c
          'c'
        when :d
          'd'
        when :e
          'e'
        else
          'asdf'
        end
  end
end

timer do
  10_000_000.times do | __ |
    x = if :asdf == :a
          'a'
        elsif :asdf == :b
          'b'
        elsif :asdf == :c
          'c'
        elsif :asdf == :d
          'd'
        elsif :asdf == :e
          'e'
        else
          'asdf'
        end
  end
end

Were you referring to some other kind of 'if/then'? I am very interested
in this, since, as I mentioned above, I need this construct several
times.

Greetings,
JS