[Veedrac]

The easy Python way:

    import sys
    import regex
    print(regex.match("\X{,12}", sys.argv[1]).group())

with the regex[1] package that should be in the stdlib Any Day Now™.

[1]: https://pypi.python.org/pypi/regex

[Spiritus]

Interesting, I had no idea the `re` module was getting revamped. Scheduled for 3.5 or later?

[Veedrac]

Certainly not 3.5, although a few years ago I would have told you almost the exact opposite.

I wouldn't hold your breath. The issue tracker[1] suggests 3.7 or 3.8 as optimistic. Guido made some comment somewhere relatively recently, but I can't find where. It's entirely possible it will never actually happen; time doesn't seem to have made people more enthusiastic.

It's a shame, because the new module is awesome.

[1] http://bugs.python.org/msg230846