From: daz <dooby@...10.karoo.co.uk>
Date: 2005-08-18T16:56:15+09:00
Subject: Re: Novice Q: What's the difference between /\s*/ and /(\s)*/?


Mike Meng wrote:

> # code
> line = '/jazz/j00319.mp3 | 2:58 | Louis Armstrong | Wonderful World'
> file, duration, artist, title = line.chomp.split(/\s*\|\s*/)
> # code end
>
> [...]
> While if I change the regex pattern in 'split' to /(\s)*\|(\s)*/,
> [...]
> What makes the differece? Any comments are appreciated.
>

Hi Mike,

You're not seeing the difference because of your assignments.
Try playing with this:

#-----------------------------------------------------------
def splt(patt)
  res = LINE.split(patt)
  print "#-> (%s)\n#-> %2d:  " % [patt.inspect, res.size]
  res.to_a.each {|col| print ' (%s)' % [col]}
  puts; puts
end

LINE = 'ABC_:_KLM_:_NOP_:_XYZ'

splt(/_:_/)
splt(/(_:_)/)
splt(/_(:)_/)
splt(/(_):(_)/)
splt(/((_):(_))/)
splt(/((_)(:)(_))/)
splt(/_:_K/)
splt(/(_:_)K/)
splt(/(_:_K)/)
splt(/((_:_K))/)
splt(/(((_:_K)))/)
#-----------------------------------------------------------

#-> (/_:_/)
#->  4:   (ABC) (KLM) (NOP) (XYZ)

#-> (/(_:_)/)
#->  7:   (ABC) (_:_) (KLM) (_:_) (NOP) (_:_) (XYZ)

#-> (/_(:)_/)
#->  7:   (ABC) (:) (KLM) (:) (NOP) (:) (XYZ)

#-> (/(_):(_)/)
#-> 10:   (ABC) (_) (_) (KLM) (_) (_) (NOP) (_) (_) (XYZ)

#-> (/((_):(_))/)
#-> 13:   (ABC) (_:_) (_) (_) (KLM) (_:_) (_) (_) (NOP) (_:_) (_) (_) (XYZ)

#-> (/((_)(:)(_))/)
#-> 16:   (ABC) (_:_) (_) (:) (_) (KLM) (_:_) (_) (:) (_) (NOP) (_:_) (_) (:) (_) (XYZ)

#-> (/_:_K/)
#->  2:   (ABC) (LM_:_NOP_:_XYZ)

#-> (/(_:_)K/)
#->  3:   (ABC) (_:_) (LM_:_NOP_:_XYZ)

#-> (/(_:_K)/)
#->  3:   (ABC) (_:_K) (LM_:_NOP_:_XYZ)

#-> (/((_:_K))/)
#->  4:   (ABC) (_:_K) (_:_K) (LM_:_NOP_:_XYZ)

#-> (/(((_:_K)))/)
#->  5:   (ABC) (_:_K) (_:_K) (_:_K) (LM_:_NOP_:_XYZ)


daz