From: dmertz@... (denis)
Date: 2004-07-16T00:12:18+09:00
Subject: Re: my ruby code won't go as fast as my perl code

"Dave Burt" <burtdav@hotmail.com> wrote in message news:<y8pJc.1797$K53.1255@news-server.bigpond.net.au>...

> 
> The main slow bit seems to be the string concatenation and comparison
> (...+$4+$5+$6 >= start_date).
> 

The addition operator always creates a new String object. So when you
chain a lot of additions you have a lot of temporary String objects
that are created. You can avoid that by using the Append ( << ) method

 (($3>='87'?'19':'20') << $3 << mm[$2] << $1 << $4 << $5 << $6 >=
start_date)

Alternatively you can use string interpolation 

 ("#{($3>='87'?'19':'20')}#{$3}#{mm[$2]}#{$1}#{$4}#{$5}#{$6}" >=
start_date)

or Array.join, like that 

([($3>='87'?'19':'20'), $3, mm[$2], $1, $4, $5, $6].join >=
start_date)

I hope it helps

Denis