From: Robert Dober <robert.dober@...>
Date: 2006-03-29T21:33:33+09:00
Subject: Re: strings and ruby style?

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On 3/29/06, Dave Burt <dave@burt.id.au> wrote:


There was a different error I forgot to initialize "actual"


Dave

Excellent idea "<<".
I do not see where there are less objects in << than in +=3D
actually.
However << is *the* operator to use. I came up with a benchmark constructin=
g
much longer strings
your << (or concat) is the *best* solution.
Another approach is not to construct strings immedeatly but to build an
array and to join the array eventually. For long strings the result is quit=
e
speactacular (almost as fast as << )
Pleas kindly look at this
-------------------------------9<------------------------------------------
647/147 > cat string2.rb;ruby string2.rb
#!/usr/bin/env ruby
 require 'benchmark'

List =3D %w{ omega delta Ringo } * 50
 n =3D 5000
 Benchmark.bm do
        |bm|
        bm.report "explicit +" do
                n.times do
                    actual =3D ''
                    List.each do
                        |x|
                        actual =3D actual + x
                    end
                end
        end # do

        bm.report "implicit +" do
                n.times do
                    actual =3D ''
                    List.each do
                        |x|
                        actual +=3D x
                    end
                end
        end # do

        bm.report "append    " do
                n.times do
                    actual =3D ''
                    List.each do
                        |x|
                        actual << x
                    end
                end
        end
        bm.report "Array     " do
                n.times do
                    actual =3D []
                    List.each do
                        |x|
                        actual << x
                    end
                    actual =3D actual.join("")
                end
        end
end
      user     system      total        real
explicit +  2.170000   0.010000   2.180000 (  2.336149)
implicit +  2.170000   0.010000   2.180000 (  2.635293)
append      0.730000   0.000000   0.730000 (  0.800968)
Array       0.770000   0.000000   0.770000 (  0.862098)

--------------------------------------10<-------------------------------

Cheers
Robert


--
Deux choses sont infinies : l'univers et la b=EAtise humaine ; en ce qui
concerne l'univers, je n'en ai pas acquis la certitude absolue.

- Albert Einstein

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