Arnaud Delobelle wrote:
> I've got to escape some unicode text according to the following map:
>
> escape_map = {
> u'\n': u'\\n',
> u'\t': u'\\t',
> u'\r': u'\\r',
> u'\f': u'\\f',
> u'\\': u'\\\\'
> }
>
> The simplest solution is to use str.replace:
>
> def escape_text(text):
> return text.replace('\\', '\\\\').replace('\n',
> '\\n').replace('\t', '\\t').replace('\r', '\\r').replace('\f', '\\f')
>
> But it creates 4 intermediate strings, which is quite inefficient
> (I've got 10s of MB's worth of unicode strings to escape)
>
> I can think of another way using regular expressions:
>
> escape_ptn = re.compile(r"[\n\t\f\r\\]")
>
> # escape_map is defined above
> def escape_match(m, map=escape_map):
> return map[m.group(0)]
>
> def escape_text(text, sub=escape_match):
> return escape_ptn.sub(sub, text)
>
> Is there a better way?
>>> escape_map = {
... u'\n': u'\\n',
... u'\t': u'\\t',
... u'\r': u'\\r',
... u'\f': u'\\f',
... u'\\': u'\\\\'
... }
>>> escape_map = dict((ord(k), v) for k, v in escape_map.items())
>>> print u"the quick\n brown\tfox
jumps\\over\\the\\lazy\\dog".translate(escape_map)
the quick\n brown\tfox jumps\\over\\the\\lazy\\dog
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