From: Mat Schaffer <schapht@...>
Date: 2006-07-28T01:12:38+09:00
Subject: String#chop slow?  REALLY slow?

I just did a quick benchmark to prove something to myself.  But I'd  
like to get a sanity check from the people on the list.

Basically I want to drop what will be a trailing "\n" from input.   
But it appears that using String#[] and if statements is nearly 200  
times more efficient than chop.   Which just seems really weird, so  
here's the benchmark.  Maybe I'm doing something wrong.

Does this seem right?  Anyone care to comment?

---- index_vs_chop.rb

require 'benchmark'

n = 100_000
bigstring = "I am a big string " * 5_000

Benchmark.bmbm do |bench|
   bench.report("Indexing") {
     n.times do
       bigstring[0..-1]
     end
   }

   bench.report("Chop") {
     n.times do
       bigstring.chop
     end
   }
end

---- end index_vs_shop.rb

output:

Rehearsal --------------------------------------------
Indexing   0.100000   0.000000   0.100000 (  0.102362)
Chop       7.190000  13.890000  21.080000 ( 22.477807)
---------------------------------- total: 21.180000sec

                user     system      total        real
Indexing   0.100000   0.000000   0.100000 (  0.108777)
Chop       7.290000  14.050000  21.340000 ( 22.755782)