From: "David A. Black" <dblack@...>
Date: 2010-05-17T21:29:46+09:00
Subject: Re: Range on strings.

Hi --

On Fri, 14 May 2010, Vikrant Chaudhary wrote:

> Hi,
> If I do -
>
> ('A'..'Z').include?('AA')
>
> It returns "true", while
>
> ('A'..'Z').to_a.include?('AA')
>
> (of course) returns "false". Is it intentional or possibly a bug?
> I'm using ruby 1.8.7 (2010-01-10 patchlevel 249) [x86_64-linux] on
> Ubuntu 10.04 x64

As per the other answers, it's because ('A'..'Z').to_a is an array of
discrete values, whereas ('A'..'Z') is a range with a start and end.
I'll just add that in Ruby 1.9, things have changed so that include?
on a range is, I think, the same as .to_a.include? and the behavior of
the old include? is found in Range#cover?

$ ruby191 -e 'p(("A".."Z").include?("AA"))'
false
$ ruby191 -e 'p(("A".."Z").cover?("AA"))'
true

include? is also available under the name member?, which I think is a
little clearer (both because include? used to mean something else, and
because being a "member" of a range doesn't really make sense so it
almost has to mean something other than just being within the range).


David

-- 
David A. Black, Senior Developer, Cyrus Innovation Inc.

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