On May 8, 2008, at 3:40 PM, Todd Benson wrote:
>  This question arises out of a couple of recent threads and may or may
>  not be a Ruby-specific question.
> 
>  I can check with a character class if one of the characters in the
>  class exists or does not exist, but can I use a regexp to check if a
>  string absolutely contains all of the characters in the class?
> 
>  Using a set perspective, I can do it like this in irb...
> 
>  s1 = "hello there"
>  s2 = "ohi"
>  (s2.unpack('c*') & s1.unpack('c*')).size == s2.size
> 
>  => false
> 
>  I use unpack to avoid creating a bunch of String objects, one for each
>  element in the array, which would happen if I used #split.  What I'm
>  wondering is if there is a way to do this with a simple regexp.
> 
>  Thanks,
>  Todd

cfp:~ >  cat a.rb
class String
   def all_chars? chars
     tr(chars, '').empty?
   end
end

p 'foobar'.all_chars?('rabof')
p 'foobar'.all_chars?('abc')
p 'foobar'.all_chars?('')



cfp:~ >  ruby a.rb
true
false
false


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