From: Todd Benson <caduceass@...>
Date: 2007-06-19T01:43:03+09:00
Subject: Re: healp reading / writing binary strings.

On 6/18/07, Melissa Silas <beingthexemplarylists@gmail.com> wrote:
> Thanks that helps.. Couple more questions..
>
> for this example:
> s = "\t\001"
> puts s[0] -> 9
> How does \t come out as 9? Is that the tab char which in turn is the
> number 9 in ascii table?

It's just the number 9, but yes you can look at it that way.
irb(main):001:0> 9.chr
=> "\t"

>
> for this example:
> s = "\001"
> Ok so now I know this is octal, does the octal value I supply correspond
> to the ascii table as well?

irb(main):002:0> 1.chr
=> "\001"
irb(main):003:0> 255.chr
=> "\377"
irb(main):004:0> 256.chr
RangeError: 256 out of char range
             from (irb):24:in 'chr'
             from (irb):24
             from :0

(I like that last "from" line :)

> for this example:
> s = "\x01"
> for hex, does the hex value I supply correspond to the ascii table as
> well?

irb(main):005:0> "\x61"
=> "a"
irb(main):006:0> ?a
=> 97

Your bytes are unprintable and so ruby simply tells you the byte
value.  What you do with that value is up to you.