Hello guys
I would like to read a hex number from an ASCII file, increment it and
write it back.
How can this be performed?
I have tried several approaches:
my file serial.txt contains: 0C
----------------------------------
f = open('serial.txt', 'r')
val = f.read()
val = val.encode('hex')
print val
----------------------------------
--> 3043
----------------------------------
f = open('serial.txt', 'r')
val = f.read()
print val
val = val+1
Check this out:
In [1]: val = '0C'
In [2]: val.encode('hex')
Out[2]: '3043'
That's not what you want. Try this:
In [3]: int(val, 16)
Out[3]: 12
And to convert an int to a hex string.
In [4]: '%x' % 13
Out[4]: 'd'
The interpreter has a help() function that gives you quick access to
information about python objects:
Help on method_descriptor:
encode(...)
S.encode([encoding[,errors]]) -> object
Encodes S using the codec registered for encoding. encoding
defaults
to the default encoding. errors may be given to set a different
error
handling scheme. Default is 'strict' meaning that encoding errors
raise
a UnicodeEncodeError. Other possible values are 'ignore',
'replace' and
'xmlcharrefreplace' as well as any other name registered with
codecs.register_error that is able to handle UnicodeEncodeErrors.
Help on class int in module __builtin__:
class int(object)
| int(x[, base]) -> integer
|
| Convert a string or number to an integer, if possible. A floating
point
| argument will be truncated towards zero (this does not include a
string
| representation of a floating point number!) When converting a
string, use
| the optional base. It is an error to supply a base when
converting a
| non-string. If the argument is outside the integer range a long
object
| will be returned instead.
|
| Methods defined here:
|
....
Unfortunately you can't use it on the '%' string formatting
operator...
SyntaxError: invalid syntax
So here's a link to the docs:
http://docs.python.org/library/stdtypes.html#string-formatting-operations
HTH,
~Simon
