parsing - How can I parse multiple (unknown) date formats in python?

Question

I have a bunch of excel documents I am extracting dates from. I am trying to convert these to a standard format so I can put them in a database. Is there a function I can throw these strings at and get a standard format back? Here is a small sample of my data:

The good thing is I know it is always Month/Day

10/02/09
07/22/09
09-08-2008
9/9/2008
11/4/2010
 03-07-2009
09/01/2010

I'd like to get them all into MM/DD/YYYY format. Is there a way I can do this without trying each pattern against the string?

Answer 1

The third-party module dateutil has a function parse that operates similarly to PHP's strtotime: you don't need to specify a particular date format, it just tries a bunch of its own.

>>> from dateutil.parser import parse
>>> parse("10/02/09", fuzzy=True)
datetime.datetime(2009, 10, 2, 0, 0)  # default to be in American date format

It also allows you to specify different assumptions:

• dayfirst – Whether to interpret the first value in an ambiguous 3-integer date (e.g. 01/05/09) as the day (True) or month (False). If yearfirst is set to True, this distinguishes between YDM and YMD. If set to None, this value is retrieved from the current parserinfo object (which itself defaults to False).
• yearfirst – Whether to interpret the first value in an ambiguous 3-integer date (e.g. 01/05/09) as the year. If True, the first number is taken to be the year, otherwise the last number is taken to be the year. If this is set to None, the value is retrieved from the current parserinfo object (which itself defaults to False).