From: Arlen Christian Mart Cuss <celtic@...>
Date: 2007-10-27T21:34:31+09:00
Subject: Re: Error in Ruby text comparison?


On Sat, 2007-10-27 at 20:27 +0900, Greg Willits wrote:
> Greg Willits wrote:
> > '1sqHmb5b8G9mN' < '1Xv5LeB9bMdar'
> > 
> > Wouldn't you think that is supposed to be TRUE ?
> Strange, this list:
> 
> s, S, s, a, B
> 
> in Excel, Numbers, and in Araelium Edit comes out as this when sorted
> 
> a, B, s, S, s
> 
> TextWrangler puts them as
> 
> a, B, s, s, S
> 
> Ruby sorts  ['s','S','s','a','B'].sort as
> 
> ["B", "S", "a", "s", "s"]

irb to the rescue:
irb(main):001:0> 'a' < 'b'
=> true
irb(main):002:0> "A" < 'b'
=> true
irb(main):003:0> "a" < "B"
=> false
irb(main):004:0> ?a < ?b
=> true
irb(main):005:0> ?A < ?b
=> true
irb(main):006:0> ?a < ?B
=> false
irb(main):007:0> ?A
=> 65
irb(main):008:0> ?a
=> 97
irb(main):009:0> 

Ruby's sorting these strings by ASCII order, and as you can see here, capital letters come first! So "A" is always less than 'a', etc.

Arlen