From: Caio Chassot <lists@...2studio.com>
Date: 2006-07-28T01:36:42+09:00
Subject: Re: String#chop slow?  REALLY slow?

> 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.

Well, if you implement chop fully, you get very similar results:

RubyMate r4106 running Ruby v1.8.4 (/usr/local/bin/ruby)
 >>> untitled

Rehearsal -------------------------------------------------
Indexing        1.790000   3.950000   5.740000 (  7.099300)
Chop            1.680000   3.930000   5.610000 (  7.135508)
Indexing crlf   1.780000   3.970000   5.750000 (  6.895291)
Chop crlf       1.670000   3.930000   5.600000 (  6.573193)
--------------------------------------- total: 22.700000sec

                     user     system      total        real
Indexing        1.780000   3.980000   5.760000 (  7.033924)
Chop            1.670000   3.970000   5.640000 (  7.297766)
Indexing crlf   1.790000   4.020000   5.810000 (  8.969243)
Chop crlf       1.680000   4.000000   5.680000 (  7.480123)

---

require 'benchmark'

n = 10_000
bigstring = "I am a big string " * 5_000

Benchmark.bmbm do |bench|
   bench.report("Indexing") {
     n.times do
       bigstring[0..-2] == "\r\n" ? bigstring[0..-2] : bigstring[0..-1]
     end
   }

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

   bigstring << "\r\n"

   bench.report("Indexing crlf") {
     n.times do
       bigstring[0..-2] == "\r\n" ? bigstring[0..-2] : bigstring[0..-1]
     end
   }

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