How to generate java .properties files in python

[Peter Otten]

Arnaud Delobelle wrote:

> I need to generate some java .properties files in Python (2.6 / 2.7).
> It's a simple format to store key/value pairs e.g.
> 
> blue=bleu
> green=vert
> red=rouge
> 
> The key/value are unicode strings.  The annoying thing is that the
> file is encoded in ISO 8859-1, with all non Latin1 characters escaped
> in the form \uHHHH (same as how unicode characters are escaped in
> Python).
> 
> I thought I could use the "unicode_escape" codec.  But it doesn't work
> because it escapes Latin1 characters with escape sequences of the form
> \xHH, which is not valid in a java .properties file.
> 
> Is there a simple way to achieve this? I could do something like this:
> 
> def encode(u):
>     """encode a unicode string in .properties format"""
>     return u"".join(u"\\u%04x" % ord(c) if ord(c) > 0xFF else c for c
> in u).encode("latin_1")
> 
> but it would be quite inefficient as I have many to generate.

>>> class D(dict):
...     def __missing__(self, key):
...             result = self[key] = u"\\u%04x" % key
...             return result
...
>>> d = D(enumerate(map(unichr, range(256))))
>>> u"ähnlich üblich nötig ΦΧΨ"
u'\xe4hnlich \xfcblich n\xf6tig \u03a6\u03a7\u03a8'
>>> u"ähnlich üblich nötig ΦΧΨ".translate(d)
u'\xe4hnlich \xfcblich n\xf6tig \\u03a6\\u03a7\\u03a8'
>>> u"ähnlich üblich nötig ΦΧΨ".translate(d).encode("latin1")
'\xe4hnlich \xfcblich n\xf6tig \\u03a6\\u03a7\\u03a8'