From: Justin Collins <justincollins@...>
Date: 2010-08-05T23:57:20+09:00
Subject: Re: String concatenation in ruby

On 08/05/2010 06:47 AM, Prachi Tripathi wrote:
> Hi,
>
> This seems to be a basic question but i would like to know why.
>
> String concatenation in rails can be done in the following three ways:
>
> 1. a+b+c
> 2. a<<b<<c
> 3. "#{a}#{b}#{c}"
>
> where a b c are three variables
>
> Which is the good way to go about concatenation and why?
>
> a+b+c is not good because it creates temp string objects i guess
>
> But i would really like to know of the three which is better and why. Is
> there any performance difference in using them
>
> Thanks in advance
>    
As you mention, using + will create strings which then need to be 
garbage collected. Using << will modify the left-most variable, which 
you may not always desire. The other downside to using + or << is that 
they will raise an error if any of your variables are not strings. If 
you use interpolation, to_s will be called on the variables which may 
save your program from crashing.

Interpolation also appears to be the fastest method: 
http://rubybenchmark.com/reports/6

-Justin