From: "Radosław Bułat" <redmine@...>
Date: 2011-01-20T18:22:25+09:00
Subject: [ruby-core:34648] [Ruby 1.9-Bug#4298][Open] Duration of calling String#[] with the same index is strangely related to string length.


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Bug #4298: Duration of calling String#[] with the same index is strangely=
 related to string length.
http://redmine.ruby-lang.org/issues/show/4298

Author: Rados=C5=82aw Bu=C5=82at
Status: Open, Priority: Normal
Category: core
ruby -v: ruby 1.8.7 (2009-12-24 patchlevel 248) [i686-darwin10.0.0], MBAR=
I 0x6770, Ruby Enterprise Edition 2010.01

The longer string is the slower is String#[] (for the same index > 0). Se=
e the example benchmark below:

<pre><code class=3D"ruby">
# encoding: utf-8

require 'benchmark'

s1 =3D "=C4=85=C4=87=C4=99=C5=82=C5=84=C3=B3=C5=9B=C5=BC=C5=BA!0123456789=
"

puts Benchmark.measure {
  1000.times { s1[1] }
}

s2 =3D "=C4=85=C4=87=C4=99=C5=82=C5=84=C3=B3=C5=9B=C5=BC=C5=BA!0123456789=
" * 100_000

puts Benchmark.measure {
  1000.times { s2[1] }
}
</code></pre>

Running above code:
<pre>
$ ruby-trunk x.rb =

  0.010000   0.000000   0.010000 (  0.000341)
  1.780000   0.020000   1.800000 (  1.998366)
</pre>


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http://redmine.ruby-lang.org

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