From: Eric Hodel <drbrain@...7.net>
Date: 2004-12-31T03:22:22+09:00
Subject: Re: seeking hints for fast io

--Apple-Mail-27--577836336
Content-Transfer-Encoding: 7bit
Content-Type: text/plain; charset=US-ASCII; format=flowed

On 30 Dec 2004, at 03:04, jm wrote:

> I have a class which holds data while it's being manipulated. The 
> trouble is that I call to_s() quite a few times printing the resulting 
> data to a file. This increases the run time of the script a surprising 
> amount raising the runtime from about 6 minutes to about 8 and a half. 
> The code looks roughly likely the following,
>
> class Example
> .
> .
>  def to_s
>    sout << "a=#{@a}"
>    sout << "b=#{@b}"
>    sout.join("\n")
>  end
> end
>
> # in main
> File.open(outfile,File::CREAT|File::RDWR|File::APPEND) do |fp|
>  the_data.each do |d|
>    fp.puts d
>    fp.puts   # add blank line
>  end
> end
>
> Anyone care to suggest a way to speed this up? Is it faster to
>
>  sout << "a=" + @a
>
> instead of
>
>   sout << "a=#{@a}"

Probably not, String#+ creates new strings, String#<< appends to an 
existing string

You can eliminate most of the method calls there though:

def to_s
   "a=#{@a}\nb=#{@b}"
end

(I realize this is probably a small example of what really happens.)

-- 
Eric Hodel - drbrain@segment7.net - http://segment7.net
FEC2 57F1 D465 EB15 5D6E  7C11 332A 551C 796C 9F04

--Apple-Mail-27--577836336
content-type: application/pgp-signature; x-mac-type=70674453;
	name=PGP.sig
content-description: This is a digitally signed message part
content-disposition: inline; filename=PGP.sig
content-transfer-encoding: 7bit

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.4 (Darwin)

iD8DBQFB1EczMypVHHlsnwQRApHRAKDf210aOCnnnpAwYNaCkPMLoNYIWgCeJ7dZ
dBUxvsyHmelU+jfCY81kVx0=
=Sq49
-----END PGP SIGNATURE-----

--Apple-Mail-27--577836336--