From: Rob Biedenharn <Rob@...>
Date: 2008-10-16T23:41:10+09:00
Subject: Re: symbol confusions!!

On Oct 16, 2008, at 9:31 AM, Jay Pangmi wrote:
> Rob Biedenharn wrote:
>>
>> Do you have a book like the Pickaxe?[1]  That will go into great
>> detail on all the features that Ruby has to offer.
>>
>> Briefly, however:
>>
>> %w{} is a way to turn a list of words into an array:
>>  %w{ one fish two fish }
>>  => [ "one", "fish", "two", "fish" ]
>>
>> %r{} is a regular expression literal.  %r{stuff.*} is like /stuff.*/
>> without having to quote slashes (which is the main reason to see it
>> used if you're matching a file path, for example)
>>
>> %7d is probably a format specification from Kernel#sprintf or  
>> String#%
>> meaning a decimal value in a minimum of 7 columns:
>>   "%7d"%42
>>   => "     42"
>>
>> Oh, and "Kernel#sprintf" (generally, ClassName#method) means the
>> instance method 'sprintf' from the class (or module) 'Kernel' (so,  
>> the
>> '%' method from the String class).
>>
>> -Rob
>>
>>
>> [1] http://www.pragprog.com/titles/ruby/programming-ruby
>>
>>
>> Rob Biedenharn    http://agileconsultingllc.com
>> Rob@AgileConsultingLLC.com
>
> Thanks Rob you made my life lot easier.. no I don't have that book I
> just have 'Agile Web Development with Rails 2nd Edt.' so, ruby is  
> just a
> small part here and hence internet has been my only source.
> Also I confusion about the use of slashes:
> %r{(\d{1,2}):(\d{1,2}):(\d{4})}
> whats the use of forward slash here
> and the '+' sign below:
> split(/[^0-9]+/)
> Also I think I've seen the use of other words with '%' like %w but I
> don't remember which words in particular.
>
> Thanks.


Brian's and Fred's responses should help, too (esp. the link to the  
earlier Pickaxe)

The \d is an escape within a regular expression that's equivalent to  
[0-9] and + is like {1,} in regular expressions to match "one or more  
of...".  x+ is xx* or x{1,}  /[^0-9]+/ is a sequence of one or more  
non-digits.

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com