From: Ryan Davis <ryand-ruby@...>
Date: 2012-02-03T08:20:15+09:00
Subject: Re: Basic Ruby performance


On Feb 2, 2012, at 14:55 , Dmitry Nikiforov wrote:

> Here's another example with significantly bigger performance difference:
> 
> Ruby:
> 
> s = "This is a test string"
> 
> re = Regexp.new( / test / )
> 
> for a in 0..1E7
>        re.match( s )
> end
> 
> Perl:
> 
> my $s = "This is a test string";
> 
> for my $a ( 0..1E7 ) {
>       $s =~ / test /;
> }
> 
> Perl takes about 1.5 seconds to execute this, while Ruby takes a 
> whopping 16!!! :((( I have a very strong feeling that I didn't compile 
> Ruby properly - there can't be such a huge difference in regexp matching 
> :(

It's all the parens, whitespace, and use of tabs that slows ruby down:

# takes 26.6 seconds on my laptop:

s = "This is a test string"

re = Regexp.new( / test / )

for a in 0..1E7
       re.match( s )
end

# takes 8.67 seconds on my laptop:

s = "This is a test string"

for a in 0..1E7
  s =~ / test /
end