casting raw strings python

Question

Given a variable which holds a string is there a quick way to cast that into another raw string variable?

The following code should illustrate what I'm after:

line1 = "hurr..\n..durr"
line2 = r"hurr..\n..durr"

print(line1 == line2)  # outputs False
print(("%r"%line1)[1:-1] == line2)  # outputs True

The closest I have found so far is the %r formatting flag which seems to return a raw string albeit within single quote marks. Is there any easier way to do this kind of thing?

score 78 · Accepted Answer · edited Oct 10 '18 at 18:37

78

Python 3:

"hurr..\n..durr".encode('unicode-escape').decode()

Python 2:

"hurr..\n..durr".encode('string-escape')

edited Oct 10 '18 at 18:37

Aran-Fey

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answered Mar 11 '10 at 19:46

Ignacio Vazquez-Abrams

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7

nice one. str.encode() with the various codecs is exactly what i was after. 'unicode-escape' actually solves another problem i was having too. cheers – dave Mar 11 '10 at 20:14
3

This doesn't work for `\w` etc. – John La Rooy Mar 11 '10 at 21:04
7

I'm getting an error in Python3.3 LookupError: unknown encoding: string-escape – Erik Apr 01 '13 at 20:16
19

@Erik, strings in Python 3 are Unicode, use `unicode-escape`. – Mark Tolonen Jun 27 '13 at 03:11
1

Don't forget that you can decode the resultant bytes into a regular Unicode string (still escaped, if you don't supply any parameters in Python 3.x), instead of still using a byte string. – Brōtsyorfuzthrāx Aug 07 '14 at 02:07
@gnibbler, There doesn't appear to be `\w` in Python. What are you referring to? Maybe you're thinking of regular expressions. – Brōtsyorfuzthrāx Aug 07 '14 at 02:12
Fails for `"X \x58"` – wim Aug 16 '19 at 18:25

Seth · Answer 2 · 2010-03-12T00:57:57.123

2

Yet another way:

>>> s = "hurr..\n..durr"
>>> print repr(s).strip("'")
hurr..\n..durr

edited Mar 12 '10 at 00:57

answered Mar 11 '10 at 19:55

Seth

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That won't work if `s` has a `'` in it – John La Rooy Mar 11 '10 at 21:07
It should be ok if the `'` is in the middle of the string, but it's definitely not robust (it's screwy with Unicode strings, for example). – Seth Mar 12 '10 at 01:01
@Seth No, it will not, because if you have `'` contained in the data then the repr will have used double quotes instead of single quotes at the edges of the string. – wim Oct 11 '18 at 03:05

score 1 · Answer 3 · answered Dec 12 '14 at 18:38

Above it was shown how to encode.

'hurr..\n..durr'.encode('string-escape')

This way will decode.

r'hurr..\n..durr'.decode('string-escape')

Ex.

In [12]: print 'hurr..\n..durr'.encode('string-escape')
hurr..\n..durr

In [13]: print r'hurr..\n..durr'.decode('string-escape')
hurr..
..durr

This allows one to "cast/trasform raw strings" in both directions. A practical case is when the json contains a raw string and I want to print it nicely.

{
    "Description": "Some lengthy description.\nParagraph 2.\nParagraph 3.",
    ...
}

I would do something like this.

print json.dumps(json_dict, indent=4).decode('string-escape')

casting raw strings python

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