From: Evan Webb <evan@...>
Date: 2004-09-23T17:22:34+09:00
Subject: Re: whitespace string only

I highly doubt a regex is faster than each_byte. each_byte has very
little code and is very fast (looping over the array in C and casting
the chars to fixnums), where as with a regex it has to pass through the
regex parser, get pulled back out as an object, pushed back into split,
which there in turn returns a potentially huge array which you pull back
again to run over with each. Then you've done another comparison with a
regex within the block which i guarantee is much slower then comparing 2
Fixnums.

My initial version didnt do \n, only white space, so here's my updated
version that even does tabs.

class String
    def only_ws?
        each_byte { |b| return false unless [9,10,32].include?(b) }
        true
    end
end

Evan Webb // evan@fallingsnow.net


On Thu, 2004-09-23 at 01:11, MiG wrote:
> I think regexp should be is faster than each_byte. What about this?
> 
> class String
> 
> def whitespace_only? str
>   str.split(/\n/).each { |x|
>      return false unless x =~ /^\s*$/
>   }
>   true
> end
> 
> end
> 
> 
> MiG
>