date.day() returns TypeError: 'int' object is not callable

Question

I'm stuck. It appears that day is being overwritten as an int somewhere. But where? Where is day becoming an int?

from datetime import *

start_date = date(1901, 1, 1)
end_date = date(2000, 12, 31)
sundays_on_1st = 0

def daterange(start_date, end_date):
    for n in range(int ((end_date - start_date).days)):
        yield start_date + timedelta(n)

for single_date in daterange(start_date, end_date):

    # type(single_date) => <type 'datetime.date'>
    # type(date.day()) => TypeError: 'getset_descriptor' object is not callable
    # type(single_date.day()) => TypeError: 'int' object is not callable
    # ಠ_ಠ 

    if single_date.day() == 1 and single_date.weekday() == 6: 
        sundays_on_1st += 1                                     

print sundays_on_1st

Answer 1

.day is not a method, you do not need to call it. Only .weekday() is a method.

if single_date.day == 1 and single_date.weekday() == 6: 
    sundays_on_1st += 1                                     

This works just fine:

>>> for single_date in daterange(start_date, end_date):
...     if single_date.day == 1 and single_date.weekday() == 6:
...         sundays_on_1st += 1
... 
>>> print sundays_on_1st
171
>>> type(single_date.day)
<type 'int'>

From the datetime.date documentation:

Instance attributes (read-only):

date.year
Between MINYEAR and MAXYEAR inclusive.

date.month
Between 1 and 12 inclusive.

date.day
Between 1 and the number of days in the given month of the given year.

It is implemented as a data descriptor (like a property) to make it read-only, hence the TypeError: 'getset_descriptor' object is not callable error you saw.