Read a formatted date in Python 2.3?

Question

I had never worked with the datetime module in Python 2.3, and I have a very silly problem. I need to read a date in the format

'10-JUL-2010'

then subtract a day (I would use timedelta), and return the string

'09-JUL-2010 00:00:00 ET'

of course, this is for hundreds of dates. While it should be trivial, I cannot find the info on how to read formatted dates in Python 2.3! Help!

Edit

I am able to retrieve the formatted date as a tuple, but it will not accept the timedelta object for subtraction! Still working on it...

** Edit **

Finally... thanks to your help I was able to solve the problem as follows:

print (datetime(*(time.strptime(date_string, format)[0:6])).strftime('%d-%b-%Y')).upper()+'00:00:00 ET'

Answer 1

You're looking for datetime.datetime.strptime(), but the documentation is awful for that function, it's effectively the reverse operation of datetime.datetime.strftime().

The format string you're looking for is: '%d-%b-%Y'

See: http://www.python.org/doc/2.3.5/lib/node211.html and http://www.python.org/doc/2.3.5/lib/datetime-datetime.html and http://www.python.org/doc/2.3.5/lib/module-time.html

Edit: Oh snap! There is no strptime in the datetime module in python 2.3. It's in the time module, you'll have to use that one instead.

Answer 2

Well, there is no builtin for that in 2.3, only from 2.5 on. But for that one format you can parse it by hand ...

months = { 'JAN' : 1, 'FEB' : 2, ... } # write that yourself :p
day,mon,year = thedate.split('-')
day = int(day)
mon = months[mon]
year = int(year)
parsed = datetime.datetime(day=day, month=month, year=year)

Answer 3

If strptime() is not working out for you there is also the option of brute forcing it with a regex:

import re
import date
timestamp_regex = re.compile(r"(\d\d)-(\w\w\w)-(\d\d\d\d)")
# month_mapping: a mapping for 3 letter months to integers
d1 = datetime.date(int(match.group(3)),          #year
                   month_mapping[match.group(2)],#month
                   int(match.group(1)))          #day