From: Xeno Campanoli / Eskimo North and Gmail <xeno.campanoli@...>
Date: 2010-06-19T06:25:09+09:00
Subject: Re: String comparison. Why does Ruby consider this true?

On 10-06-18 02:21 PM, Josh Cheek wrote:
> On Fri, Jun 18, 2010 at 4:09 PM, Michael Fellinger<m.fellinger@gmail.com>wrote:

I thought Unicode started with ASCII anyway, so I don't think that solves it...

Yes, here:

http://www.tamasoft.co.jp/en/general-info/unicode.html
>
>> 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])
>


-- 
"It's the preponderance, stupid!" - Professor Stephen Schneider, IPCC member