From: Joel VanderWerf <vjoel@...>
Date: 2007-11-03T11:25:15+09:00
Subject: Re: ActAsHash

Marcin Raczkowski wrote:
> Joel VanderWerf wrote:
>> Marcin Raczkowski wrote:
>>>     self.instance_variable_get(("@"+index.to_s).to_sym)
>>
>> ISTR that "@"+index.to_s is slower than "@#{index}".
> i think concantation is faster then creating new one and i have no idea 
> what ISTR mean

Eh. It's not as much as I remembered:

require 'benchmark'

Benchmark.bmbm(12) do |bm|
   n = 1_000_000
   index = "foo"
   @foo = 123

   bm.report('"@"+index.to_s') do
     n.times do
       instance_variable_get("@"+index.to_s)
     end
   end

   bm.report('"@#{index}"') do
     n.times do
       instance_variable_get("@#{index}")
     end
   end
end

__END__

Rehearsal --------------------------------------------------
"@"+index.to_s   1.170000   0.010000   1.180000 (  1.178025)
"@#{index}"      0.960000   0.000000   0.960000 (  0.954115)
----------------------------------------- total: 2.140000sec

                      user     system      total        real
"@"+index.to_s   1.170000   0.000000   1.170000 (  1.174559)
"@#{index}"      0.940000   0.000000   0.940000 (  0.945398)


ISTR that ISTR means I seem to recall, but I might be wrong ;)

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407