[Python-Dev] Broken strptime in Python 2.3a1 & CVS (original) (raw)

Guido van Rossum guido@python.org
Tue, 14 Jan 2003 16:30:29 -0500

> The C wrapper around strptime.strptime() stays, of course. It > currently has a bit of an inefficiency (what happens when it tries to > import strptime is a lot more than I'd like to see happen for each > call) but that's a somewhat tricky issue that I'd like to put off for > a little while; I've added a SF bug report as a reminder. (667770) >

Anything I can do to help with that? If it is just a matter of re-coding it in a certain way just point me in the direction of docs and an example and I will take care of it.

The issues are really subtle. E.g. you can't just store the python strptime function in a global, because of multiple independent interpreters and reload(). You can't peek in sys.modules because of rexec.py.

If you still want to look into this, be my guest.

And to comment on the speed drawback: there is already a partial solution to this. strptime has the ability to return the regex it creates to parse the data string and then subsequently have the user pass that in instead of a format string::

strptimeregex = strptime.strptime('%c', False) #False triggers it

Why False and not None?

for line in logfile: timetuple = strptime.strptime(strptimeregex, line)

That at least eliminates the overhead of having to rediscover the locale information everytime. I will add a doc patch with the patch that I am going to do that adds the default values explaining this feature if no one has objections (can only think this is an issue if it is decided it would be better to write the whole thing in C and implementing this feature would become useless or too much of a pain).

Yeah, but this means people have to change their code. OK, I think for speed hacks that's acceptable.

--Guido van Rossum (home page: http://www.python.org/~guido/)