<s>[INST] Get Last Day of the Month in Python Is there a way using Python's standard library to easily determine (i.e. one function call) the last day of a given month?
If the standard library doesn't support that, does the dateutil package support this?
 [/INST] I didn't notice this earlier when I was looking at the documentation for the calendar module, but a method called monthrange provides this information:

monthrange(year, month)
      Returns weekday of first day of the month and number of days in month, for the specified year and month. 

>>> import calendar
>>> calendar.monthrange(2002,1)
(1, 31)
>>> calendar.monthrange(2008,2)
(4, 29)
>>> calendar.monthrange(2100,2)
(0, 28)

so:
calendar.monthrange(year, month)[1]

seems like the simplest way to go.
Just to be clear, monthrange supports leap years as well:
>>> from calendar import monthrange
>>> monthrange(2012, 2)
(2, 29)

My previous answer still works, but is clearly suboptimal.
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