From: Kirk Haines <wyhaines@...>
Date: 2010-06-19T03:01:29+09:00
Subject: Re: String comparison. Why does Ruby consider this true?

On Fri, Jun 18, 2010 at 11:46 AM, 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?

Uppercase letters come before lowercase letters.

You can look at the implementation in the source (start at
rb_str_cmp()), but if you dig deeply enough, it comes down to the way
the standard C library function memcmp() works. It compares bytes. And
an ASCII 'X' is represented by a smaller value (88) than an ASCII 'b'
(98).  So 'Xeo' is less than 'ball'.


Kirk Haines
Developer
Engine Yard