From: Josh Cheek <josh.cheek@...>
Date: 2010-06-19T06:21:33+09:00
Subject: Re: String comparison. Why does Ruby consider this true?

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On Fri, Jun 18, 2010 at 4:09 PM, Michael Fellinger <m.fellinger@gmail.com>wrote:

> On Sat, Jun 19, 2010 at 3:43 AM, Josh Cheek <josh.cheek@gmail.com> wrote:
> > On Fri, Jun 18, 2010 at 12:46 PM, Abder-rahman Ali <
> > abder.rahman.ali@gmail.com> wrote:
> >
> >> When I try for example to compare the following strings in Ruby, I get
> >> "true".
> >>
> >> puts 'Xeo' < 'ball'
> >>
> >> When I make 'Xeo' start with a lowercase letter, i get 'false'
> >>
> >> puts 'xeo' < 'ball'
> >>
> >> The second statement is clear, but why when I capitalize 'Xeo' I get
> >> true?
> >>
> >> Thanks.
> >> --
> >> Posted via http://www.ruby-forum.com/.
> >>
> >>
> > Well, this used to be easy to show, but apparently since ascii has been
> > abandoned, and I don't know unicode, I have to resort to hacky things
> like
> > this to explain it.
> >
> >
> > $chars = (1..128).inject(Hash.new) { |chars,num| chars[num.chr] = num ;
> > chars }
> >
> > def to_number_array(str)
> >  str.split(//).map { |char| $chars[char] }
> > end
> >
> > to_number_array 'Xeo'   # => [88, 101, 111]
> > to_number_array 'xeo'   # => [120, 101, 111]
> > to_number_array 'ball'  # => [98, 97, 108, 108]
> > to_number_array 'ABC'   # => [65, 66, 67]
> > to_number_array 'abc'   # => [97, 98, 99]
>
> >> %w[Xeo xeo ball ABC abc].sort.each{|word| p word => word.codepoints.to_a
> }
> {"ABC"=>[65, 66, 67]}
> {"Xeo"=>[88, 101, 111]}
> {"abc"=>[97, 98, 99]}
> {"ball"=>[98, 97, 108, 108]}
> {"xeo"=>[120, 101, 111]}
> => ["ABC", "Xeo", "abc", "ball", "xeo"]
>
>
> --
> Michael Fellinger
> CTO, The Rubyists, LLC
>
>

Thanks, but it doesn't seem to work on 1.8


RUBY_VERSION # => "1.8.7"

%w[Xeo xeo ball ABC abc].sort.each{|word| p word => word.codepoints.to_a } #
=>
# ~> -:3: undefined method `codepoints' for "ABC":String (NoMethodError)
# ~>     from -:3:in `each'
# ~>     from -:3




And the 1.8 ways to get it don't work on 1.9 (ie "a"[0])

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