From: Joel VanderWerf <vjoel@...>
Date: 2004-05-28T09:24:19+09:00
Subject: Re: Nasty string growth performance

Tom Trebisky wrote:
> 	    buf = ""
...
>                 buf += line

and

> 	    buf = Array.new
...
>                 buf.push line

are not comparable constructs.

The first one is the same as

   buf = buf + line

which constructs a new string each time. The second one modifies the 
existing array in place, which is why you saw better performance.

What you probably want is

   buf << line

This just concatenates line on the end of the buf string, modifying buf 
in place. An advantage of this is that the same code works whether buf 
is a String or an Array (Array#<< is the same as Array#push).