The reverse of encode('...', 'backslashreplace')

[=?ISO-8859-1?Q?Tor_Erik_S=F8nvisen?=]

Hi,

How can I transform b so that the assertion holds? I.e., how can I
reverse the backslash-replaced encoding, while retaining the str-type?

>>a = u'æ'
>>b = a.encode('ascii ', 'backslashrepla ce')
>>b

'\\xe6'

>>assert isinstance(b, str) and b == 'æ'

Traceback (most recent call last):
File "<pyshell#5 9>", line 1, in <module>
assert isinstance(b, str) and b == 'æ'
AssertionError

Regards,
tores

[Duncan Booth]

Re: The reverse of encode('...', 'backslashrepla ce')

"Tor Erik Sønvisen" <torerik81@gmai l.comwrote:

How can I transform b so that the assertion holds? I.e., how can I
reverse the backslash-replaced encoding, while retaining the str-type?
>

>>>a = u'‘'
>>>b = a.encode('ascii ', 'backslashrepla ce')
>>>b

'\\xe6'

>>>assert isinstance(b, str) and b == '‘'

>
Traceback (most recent call last):
File "<pyshell#5 9>", line 1, in <module>
assert isinstance(b, str) and b == '‘'
AssertionError
>

The simple answer is that you cannot: the backslashreplac e isn't a
reversible operation. e.g. Try:

>>a = u'\\xe6æ'
>>print a

\xe6æ

>>b = a.encode('ascii ', 'backslashrepla ce')
>>b

'\\xe6\\xe6'

>>>

There is no way after the encoding that you can tell which of the \xe6
sequences needs reversing and which doesn't. Perhaps the following is
what you want:

>>b = a.encode('unico de_escape')
>>print b

\\xe6\xe6

>>print b.decode('unico de_escape')

\xe6æ

>>>