Python convert date string to python date and subtract
Question: I have a situation where I need to find the previous date from the
`date_entry` where the `date_entry` is string, I managed to do this:

    
    
    >>> from datetime import timedelta, datetime
    >>> from time import strptime, mktime
    >>> date_str = '20130723'
    >>> date_ = strptime(date_str, '%Y%m%d')
    >>> date_
    time.struct_time(tm_year=2013, tm_mon=7, tm_mday=23, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=1, tm_yday=204,tm_isdst=-1)
    >>> datetime.fromtimestamp(mktime(date_))-timedelta(days=1)
    datetime.datetime(2013, 7, 22, 0, 0)
    >>>
    

But, for this I have to import the modules `timedelta`, `datetime`, `strptime`
and `mktime`. I think this really an overkill to solve this simple problem.

Is there any more elegant way to solve this (using Python 2.7) ?


Answer: Just use
[datetime.datetime.strptime](http://docs.python.org/2/library/datetime.html#datetime.datetime.strptime)
class method:

    
    
    >>> import datetime
    >>> date_str = '20130723'
    >>> datetime.datetime.strptime(date_str, '%Y%m%d') - datetime.timedelta(days=1)
    datetime.datetime(2013, 7, 22, 0, 0)
    

