From: Robert Klemme <shortcutter@...>
Date: 2010-11-04T17:11:05+09:00
Subject: Re: Regular Expression

On Wed, Nov 3, 2010 at 5:45 PM, w_a_x_man <w_a_x_man@yahoo.com> wrote:
> On Nov 3, 7:31 am, Robert Klemme <shortcut...@googlemail.com> wrote:

>> I'd rather do:
>>
>> def check(input)
>>  raise ArgumentError, "Illegal chars in sequence: %p" % input unless
>> /\A[A-D]{0,4}\z/ =~ input
>>  cnt = {'A' => 1, 'B' => 1, 'C' => 1, 'D' => 2}
>>  input.scan /./ do |m|
>>    raise ArgumentError, "Illegal sequence %p" % input if (cnt[m] -= 1) < 0
>>    # alt: return false
>>  end
>>  # alt: true
>> end
>
> "We don't need no stinkin' loops!"
>
> def check input
>  return false  unless /\A[A-D]{0,4}\z/ =~ input
>  %w(A B C D).map{|s| input.count s}.zip( [1,1,1,2] ).
>    map{|a,b| b-a}.all?{|n| n >= 0}
> end

The question is: what qualifies as a loop?  Explicit loops are only
done with "while", "until" and "for",  Everything else is just a
method call with a block.

According to the strict loop definition my code does not have a loop
either.  According to the wide loop definition your code has a lot
more loops than mine.  I can spot at least five of them - plus a lot
temporary Array instances.

Cheers

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/