From: Michael Libby <michael.c.libby@...>
Date: 2008-11-23T01:09:31+09:00
Subject: Re: Need help understand an expression

On Sat, Nov 22, 2008 at 9:35 AM, Buzz Hill <buzzhill@verizon.net> wrote:
> Hi,
>
>
> Can someone explain the role of the "?" before the "x"
>
> s = "abcdefg"
> s[0] = ?x       # s == "xbcdef"
>
>
> I know this will accomplish the same thing.
>
>  s[0] = 'x'

irb(main):004:0> ?a
=> 97

It's an integer value keyword.

http://ruby-doc.org/docs/ProgrammingRuby/html/language.html has more
information under "Integer and Floating Point Numbers"

irb(main):005:0> x = " "
=> " "
irb(main):006:0> x[0] = ?a
=> 97
irb(main):007:0> x
=> "a"

End result for the string you modify is the same because String#[]=
with a single integer index accepts either integers or strings.

irb(main):002:0> x[0] = 'abc'
=> "abc"
irb(main):003:0> x
=> "abc"

-Michael Libby