From: Jano Svitok <jan.svitok@...>
Date: 2007-12-06T21:38:40+09:00
Subject: Re: if /hello/ =~line

On Dec 6, 2007 12:49 PM, Lee Jarvis <ljjarvis@gmail.com> wrote:

Sometimes it's better to cache the /#{var}/ as in this case, new
regexp object is created on each pass through the cycle.
That might hurt the performance a bit. So:

> var = "hello"
+ var_re = /#{var}/
> File.foreach "file.txt" do |line|
-   if /#{var}/ =~ line
+   if var_re =~ line
>     puts "found it"
>     break
>   end
> end

(This might apply for 1.8 MRI only, other interpreters might be
different): When the regex literal contains #{}, the object
is created on each pass through the code. In the other case it's
created only once.

Jano