Maketrans in Python 2.6

Question

I have got this nice little method to remove control characters from a string. Unfortunatelly, it does not work in Python 2.6 (only in Python 3.1). It states:

mpa = str.maketrans(dict.fromkeys(control_chars))

AttributeError: type object 'str' has no attribute 'maketrans'

def removeControlCharacters(line):
   control_chars = (chr(i) for i in range(32))
   mpa = str.maketrans(dict.fromkeys(control_chars))
   return line.translate(mpa)

How can it be rewritten?

Answer 1

In Python 2.6, maketrans is in the string module. Same with Python 2.7.

So instead of str.maketrans, you'd first import string and then use string.maketrans.

Answer 2

For this instance, there is no need for maketrans for either byte strings or Unicode strings:

Python 2.6.6 (r266:84297, Aug 24 2010, 18:46:32) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> delete_chars=''.join(chr(i) for i in xrange(32))
>>> '\x00abc\x01def\x1fg'.translate(None,delete_chars)
'abcdefg'

or:

Python 2.6.6 (r266:84297, Aug 24 2010, 18:46:32) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> delete_chars = dict.fromkeys(range(32))
>>> u'\x00abc\x01def\x1fg'.translate(delete_chars)
u'abcdefg'

or even in Python 3:

Python 3.1.3 (r313:86834, Nov 27 2010, 18:30:53) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> delete_chars = dict.fromkeys(range(32))
>>> '\x00abc\x01def\x1fg'.translate(delete_chars)
'abcdefg'

See help(str.translate) and help(unicode.translate) (in Python2) for details.