Python - string of binary escape sequences as literal

Question

I need to print out a string of binary escape sequences, e.g. \x05\x03\x87, exactly as they appear. When I try to print them, Python returns a string of weird non-ASCII characters. How can I print them as a string literal?

Answer 1

repr

>>> a='\x05\x03\x87'
>>> print a
?
>>> print repr(a)
'\x05\x03\x87'

EDIT

Sven makes the point that the OP might want every character dumped in hex, even the printable ones, in which case, the best solution I can think of is:

>>> print ''.join(map(lambda c:'\\x%02x'%c, map(ord, a)))
\x05\x03\x87

ADDITIONAL EDIT

Four years later, it occurs to me that this might be both faster and more readable:

>>> print ''.join(map(lambda c:'\\x%02x'% ord(c), a))

or even

>>> print ''.join([ '\\x%02x'% ord(c) for c in a ])

Answer 2

Use the string-escape encoding:

>>> print '\x05\x03\x87'.encode('string-escape')
\x05\x03\x87

From docs:

Produce a string that is suitable as string literal in Python source code

This will essentially give you the same thing as repr(), without those pesky quotes.

Note that like Malvolio's answer, this assumes that you only want the escaped version for non-printable characters, if this is not what you want please clarify.

Answer 3

You can derive your own subclass of str that behaves & prints the way you desire, yet can be used almost anywhere a regular string could be and has all the same built-in methods.

As you can see, the example prints the hex values of all the characters it contains, whether they're printable normally or not -- something which could be done differently if you wanted, of course.

class HexStr(str):
    def __repr__(self):
        return "'" + ''.join('\\x{:02x}'.format(ord(ch)) for ch in self) + "'"
    __str__ = __repr__

a = HexStr('abc\x05\x03\x87')
print a
print str(a)
print repr(a)

Output:

'\x61\x62\x63\x05\x03\x87'
'\x61\x62\x63\x05\x03\x87'
'\x61\x62\x63\x05\x03\x87'