Determine if datetime object is date or datetime-CodePudding

I am trying to format datetime objects, and I wrote a little function to determine if the datetime object is a date or datetime object. But, nothing I've tried works.

Generating date and date times with datetime.date.today() and datetime.datetime.now() and assigning that to dtDate.

My first attempt was isinstance() :

dtDate = datetime.date.today()
# dtDate = datetime.datetime.now()

if isinstance(dtDate, date) :
        sDate = dtDate.strftime('%x')
    elif isinstance(dtDate, datetime) :
        sDate = dtDate.strfttime('%x %X')

But that triggers regardless of whether it is a date or datetime. If I am more specific, like 'datetime.date' says 'arg 2 must be type or tuple'.

I also tried to detect if the object had the hour field :

if dtDate.hour :
    sDate = dtDate.strftime('%x %X')
else :
    sDate = dtDate.strfttime('%x')

But, that freaks out if the object is purely a date, without an hour attribute.

Even a try/except block has issues :

try :
    if dtDate.hour :
        sDate = dtDate.strftime('%x %X')
except :
    sDate = dtDate.strfttime('%x')

This returns 'datetime.date' object has no attribute 'strfttime' for date objects.

Lastly, I tried to compare types :

if type(dtDate) is datetime.date :
    sDate = dtDate.strftime('%x')
else :
    sDate = dtDate.strfttime('%x %X')

Returns properly for date, but not datetime objects (returns 'datetime.datetime' object has no attribute 'strfttime')

Sorry for the brain dump, but I am completely out of ideas.

CodePudding user response：

If you look at the source code for the datetime class (or simply command click on datetime using an IDE on Mac), you'll notice that the datetime class actually is a subclass of date:

class datetime(date):
    ...

Therefore, isinstance(dtDate, date) will be true even if dtDate is a datetime object.

You can fix this by checking for the more specific type first:

if isinstance(dtDate, datetime):
    sDate = dtDate.strftime('%x %X')
elif isinstance(dtDate, date):
    sDate = dtDate.strftime('%x')

Full code:

from datetime import date, datetime

#  dtDate = date.today()
dtDate = datetime.now()

if isinstance(dtDate, datetime):
    sDate = dtDate.strftime('%x %X')
elif isinstance(dtDate, date):
    sDate = dtDate.strftime('%x')

print(sDate)