CODEWITHSUNDEEP
pythonarraysdecode
honeyfuzz
honeyfuzz

Reputation: 11

convert byte array to string without interpreting the bytes?

I have a GSM date/time stamp from a PDU encoded SMS it is formatted as so

\x90,\x21,\x51,\x91,\x40,\x33

format yy,mm,dd,hh,mm,ss

I have read them from a binary file into a byte array. I want to convert them to a string but without doing any decoding I want to end up with a string that contains 902151914033. I then need to reverse each 2 characters in the string.

Can anyone give me some pointers? Many Thanks

Upvotes: 1

Views: 10756

Answers (5)

tzot
tzot

Reputation: 95901

switcher= dict(
    (n1*16 + n2, n2*16 + n1)
    for n1 in range(16)
    for n2 in range(16)
)

def nibble_switcher(bindata):
    return type(bindata)(switcher[i] for i in bindata)
    # will work with many types, not only bytearray

def nibble_switcher_as_hex_string(bindata):
    return ''.join("%02x" % i for i in nibble_switcher(bindata))

Upvotes: 0

charstar
charstar

Reputation: 1167

If, in your question, the string you have provided is the literal set of bytes (as ascii) including the \ and , and you wish to strip them out you could use the binascii module and str.replace:

import binascii
qp = binascii.b2a_qp( bunchabytes )
plainstring = qp.replace( '\\x', '' ).replace( ',', '' )

The resultant plainstring will consist of only the digits.

Upvotes: 0

Hamish Grubijan
Hamish Grubijan

Reputation: 10820

This should get you started:

>>> s = b'\x90\x21\x51\x91\x40\x33'
>>> lst = [hex(z)[2:] for z in s]
>>> lst
['90', '21', '51', '91', '40', '33']

>>> string = ''.join(hex(z)[3:1:-1] for z in s)
>>> string
'091215190433'

Upvotes: 5

James
James

Reputation: 25513

What you mean is that you do want to do some processing! The unprocessed bytes are most easily represented as characters.

I think what you want is something along the lines of:

r = ''
for num in array:
    r += '%2X' % num
return r

Which I'm sure could be wrapped up in an anonymous function, if necessary.

Upvotes: 1

Out of Hanwell
Out of Hanwell

Reputation: 81

To convert to hex:

hexdata = ''.join('%02x' % ord(byte) for byte in bindata)

To reverse every other hex character (if I'm understanding correctly):

hexdata = ''.join(('%02x' % ord(byte))[::-1] for byte in bindata)

Upvotes: 5

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