ASCII code thing...what gives?

ruby-talk
1

Hello,

irb(main):001:0> ?T
=> 84

irb(main):002:0> "\84"
=> "84"

irb(main):003:0> "\124"
=> "T"

irb(main):004:0> "\124\84"
=> "T84"

What? Do these operators not do what I think they should?

Todd

2

I think the correct way is not

\number -> char

but

number.chr -> char

65.chr -> "A"

try that:

···

(1..255).each {|x| puts "#{x} -> #{x.chr}" }

--- Ursprüngliche Nachricht ---
Von: "Todd" <toddkennethbenson@yahoo.com>
An: ruby-talk@ruby-lang.org (ruby-talk ML)
Betreff: ASCII code thing...what gives?
Datum: Wed, 9 Nov 2005 04:57:12 +0900

Hello,

irb(main):001:0> ?T
=> 84

irb(main):002:0> "\84"
=> "84"

irb(main):003:0> "\124"
=> "T"

irb(main):004:0> "\124\84"
=> "T84"

What? Do these operators not do what I think they should?

Todd

3

Hi,

irb(main):001:0> ?T
=> 84

irb(main):002:0> "\84"
=> "84"

irb(main):003:0> "\124"
=> "T"

irb(main):004:0> "\124\84"
=> "T84"

8 is too big for octal... :slight_smile: So I think the \8 is just ignored, leaving the literal "84".

Regards,

Bill

···

From: "Todd" <toddkennethbenson@yahoo.com>

4

That 124 octal equals 84 decimal may be a clue. I don't have my Ruby docs here or I'd look further myself.

···

On Nov 8, 2005, at 2:57 PM, Todd wrote:

Hello,

irb(main):001:0> ?T
=> 84

irb(main):002:0> "\84"
=> "84"

irb(main):003:0> "\124"
=> "T"

irb(main):004:0> "\124\84"
=> "T84"

What? Do these operators not do what I think they should?

Todd

----
Bob Hutchison -- blogs at <http://www.recursive.ca/hutch/&gt;
Recursive Design Inc. -- <http://www.recursive.ca/&gt;
Raconteur -- <http://www.raconteur.info/&gt;

5

Hello,

irb(main):001:0> ?T
=> 84

irb(main):002:0> "\84"
=> "84"

irb(main):003:0> "\124"
=> "T"

irb(main):004:0> "\124\84"
=> "T84"

What? Do these operators not do what I think they should?

84 is 124 in octal.

Hope that helps,
Jeff

···

On Wed, Nov 09, 2005 at 04:57:12AM +0900, Todd wrote:

Todd

6

irb(main):001:0> ?T
=> 84

The '?' operator returns the ascii code of the character

irb(main):002:0> "\84"
=> "84"

I think this is evaluated as "\8" and "4". "\x" returns "x" so "84"
makes sense.

Note: there is no decimal substitution only "\nnn" (octal) and "\xnn"
(hex).

irb(main):003:0> "\124"
=> "T"

This matches the octal form a substitution so it is correct.

irb(main):004:0> "\124\84"
=> "T84"

As previously shown the first part matches the octal substitution
"\124" => "T". The second part matches "\8" + "4" => "84". Thus "T84"
is correct.

7

Dale Martenson wrote:

> irb(main):001:0> ?T
> => 84

The '?' operator returns the ascii code of the character

> irb(main):002:0> "\84"
> => "84"

I think this is evaluated as "\8" and "4". "\x" returns "x" so "84"
makes sense.

Note: there is no decimal substitution only "\nnn" (octal) and "\xnn"
(hex).

> irb(main):003:0> "\124"
> => "T"

This matches the octal form a substitution so it is correct.

> irb(main):004:0> "\124\84"
> => "T84"

As previously shown the first part matches the octal substitution
"\124" => "T". The second part matches "\8" + "4" => "84". Thus "T84"
is correct.

Yes, thanks to everyone for the quick response. I don't even know
where I originally heard of the "\nn" operator, so couldn't find the
doc on it (maybe Pickaxe?).

my_num.chr will work perfect.

Thanks again,
Todd

8

Todd wrote:

Yes, thanks to everyone for the quick response. I don't even know
where I originally heard of the "\nn" operator, so couldn't find the
doc on it (maybe Pickaxe?).

Programming Ruby (original)

The Ruby Language -> The Basic Types -> Strings

http://www.rubycentral.com/book/language.html#UD

daz