From: 7stud -- <bbxx789_05ss@...>
Date: 2008-05-14T01:45:49+09:00
Subject: Re: How to convert character to hexadecimal?

Chris Hulan wrote:
> On May 13, 9:57 am, I�aki Baz Castillo <i...@aliax.net> wrote:
>> Great !
>>
>> --
>> I�aki Baz Castillo
>> <i...@aliax.net>
> 
> I think ' '[0].to_s.hex will produce the value and be a bit easier to
> read.  YMMV
> For example:
>   x = " \tX"
>   0.upto(x.size-1){|i| puts "x%02x"%x[i].to_s.hex}
> 

Besides being a candidate to win a code obfuscation competition, your 
code doesn't give the proper results.  For instance, if you start with 
the string "abc":

x = "abc"
0.upto(x.size-1){|i| puts "x%02x"%x[i].to_s.hex}

--output:--
x97
x98
x99


Those are the ascii values written with an x in front.  You don't 
convert decimal numbers to hex by merely writing an "x" in front of 
them.  The hex value x97 is equal to 9*16 + 7*1 = 151 in decimal, which 
is not the ascii code for an "a".  The ascii code for an "a" is 97.

Your problems are a direct result of trying to cram all the code into 
one line as well as using 'x' as a variable name, a character in the 
string, a type specifier in the format string, and as the leading 
charcacter in the output!

This works:

str = " \tC"

0.upto(str.length - 1) do |i|
  ascii_code = str[i]
  hex_str = ascii_code.to_s(16)

  if hex_str.length == 1
    hex_str = "0x0#{hex_str}"
  else
    hex_str = "0x#{hex_str}"
  end

  puts hex_str
end

--output:--
0x20
0x09
0x43


Or, you can use the cryptic format specifiers like this:

str = " \tC"

0.upto(str.length - 1) do |i|
  ascii_code = str[i]
  dec_str = ascii_code.to_s

  puts "%#04x" % dec_str
end

--output:--
0x20
0x09
0x43



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