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I am trying to write a function to return True if a string that is passed to it is binary. How can i run this Python 2.x code under Python 3.4.3? This is the error I am getting:

TypeError: translate() takes exactly one argument (2 given)

the code:

textchars = bytearray([0,7,8,9,10,12,13,27]) + bytearray(range(0x20, 0x100))
is_binary_string = lambda data: bool(data.translate(None,textchars))

I read up on the documentation for str.maketrans() but don't understand how to incorporate it into the code.

Anand S Kumar
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jftuga
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1 Answers1

1

In Python 3.4 , you no longer have deletechars param , instead you can pass a dictionary of mappings to str.translate() , and for all elements that you want to delete, you can use empty string '' as the value. In your case, the code would become -

from itertools import zip_longest
textchars = bytearray([0,7,8,9,10,12,13,27]) + bytearray(range(0x20, 0x100))
textdict = dict(zip_longest(textchars,[''],fillvalue=''))
is_binary_string = lambda data: bool(data.translate(textdict))

The above code would assign empty string to all elements in textchars , since that is what you want as well.

Example/Demo -

>>> textchars = bytearray([0,7,8,9,10,12,13,27]) + bytearray(range(0x20, 0x100))
>>> from itertools import zip_longest
>>> textdict = dict(zip_longest(textchars,[''],fillvalue=''))
>>> pprint.pprint(textdict)
{0: '',
 7: '',
 8: '',
 9: '',
 10: '',
 12: '',
 13: '',
 27: '',
 32: '',
 33: '',
 34: '',
 35: '',
 36: '',
 37: '',
 38: '',
 39: '',
 40: '',
 41: '',
 42: '',
 43: '',
 44: '',
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 50: '',
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 252: '',
 253: '',
 254: '',
 255: ''}
>>> 'abcdef'.translate(textdict)
''

If data is a byte-string, then you can still use the previous code from `Python 2.x here - Example -

>>> textchars = bytearray([0,7,8,9,10,12,13,27]) + bytearray(range(0x20, 0x100))
>>> b'abcdefasdas'.translate(None,textchars)
b''
Anand S Kumar
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  • I am seeing:`TypeError: 'dict' does not support the buffer interface` on the `is_binary_string =` line – jftuga Aug 19 '15 at 18:35
  • You would need to decode the byte-string to a string before using `translate` . In Python 3.x , normal string is unicode string, whereas in Python 2.x , normal strings are bytestring. – Anand S Kumar Aug 19 '15 at 18:37
  • Deocde using - `data.decode('utf-8')` or whatever encoding you prefer – Anand S Kumar Aug 19 '15 at 18:38
  • Also, if what you have is a byte-string, then you can use previous Python 2 method itself, as I have updated in my answer. – Anand S Kumar Aug 19 '15 at 18:40
  • I tried decode() with utf-8, latin-1 and it did not work. I am definitely passing in a `str` type. I get the same error. – jftuga Aug 19 '15 at 18:50
  • Can you update the question with the latest code, including how you are passing in the data for testing, and the complete traceback? – Anand S Kumar Aug 19 '15 at 18:50