Odd problem with converting string to Hex?

[Benjamin Schollnick]

I haven't tried this.... But it certainly makes sense...

I was assuming, incorrectly it appears, that Python was storing it 
as a string of 3 or so characters.... After all, that's what the 
Print command was displaying....

I had never considered that it was being stored as a "list of 
characters", array, or whatever you'd like to call it....

Although, I want to stress STR(data....), didn't give a HEX PRINTABLE
result.... 

I'll try this, and hopefully all will be well....

Thanks for the assistance!

         - Benjamin


In article <OUK%6.17065$he.735624 at e420r-atl1.usenetserver.com>,
 "Steve Holden" <sholden at holdenweb.com> wrote:

> "Benjamin Schollnick" <junkster at rochester.rr.com> wrote in ...
> > Folks,
> >
> >    This is odd.... or at least I think it is....
> >
> >    Using Python v2.1....
> >
> >    Here's a snippet of the data:
> >
> > ('.1.3.6.1.2.1.2.2.1.6.2', '\x00\x90\x83H\x11\x0f'),
> > ('.1.3.6.1.2.1.2.2.1.6.1', '\x00\x90\x83H\x11\x0f'),
> > ('.1.3.6.1.2.1.2.2.1.2.4', 'RF Upstream Interface')
> >
> >    I've tried using:
> >
> >       eval (data[1])
> >       hex (data[1])
> >       str(data[1])
> >
> >    What gets returned is:
> >
> >    Unknown - Mac?  --->    êÉH
> >             Hex:            Long:
> >
> Let's get this straight. Your data records MAC-level addresses as six-byte
> strings, and you want to represent each address as a set of byte values, in
> hex, separated by dashes. OK so far?
> 
> >    Which os definetly not what I'm looking for.... I'm attempting to
> > decode this in pure hexadecimal...
> >
> >    I suspect it's due to the "\x" in the string, but I can't pull up the
> > documentation, since when I tried I wasn't getting a response from
> > python.org.....
> >
> Nope. There *is* no"\x" in the string. Look:
> 
> >>> d = ('.1.3.6.1.2.1.2.2.1.6.2', '\x00\x90\x83H\x11\x0f')
> >>> len(d[1])
> 6
> 
> Each \xXX (where the XX are hex digits) is made into a single 8-bit
> character by the Python interpreter. The "H" is also a character. Let's look
> at the decimal values of each character:
> 
> >>> [ord(x) for x in d[1]]
> [0, 144, 131, 72, 17, 15]
> 
> Given the hex values in your data this seems reasonable.
> 
> >    Conceptually I'm trying to output it, similiar to:
> >
> >       00-90-83-11-0f    Assuming I'm reading the returned data properly.
> 
> That appears to be the problem: you assumed that Python was storing
> everything inside the single quotes as individual bytes, when in fact the
> hex escape sequences are interpreted as the string is constructed.
> 
> Getting the hex values is relatively easy using string formatting:
> 
> >>> ['%02x' % ord(x) for x in d[1]]
> ['00', '90', '83', '48', '11', '0f']
> 
> All you have to do to get what you want is join this list of strings with
> dashes. I tend to favor the string methods for this kind of thing, though
> some say it seems counterintuitive:
> 
> >>> "-".join(['%02x' % ord(x) for x in d[1]])
> '00-90-83-48-11-0f'
> 
> Hope this helps.
> 
> regards
>  STeve
> --
> http://www.holdenweb.com
> 
> 
>