Get hour of year from a Datetime

Question

Is there a simple way to obtain the hour of the year from a datetime?

dt = datetime(2019, 1, 3, 00, 00, 00) # 03/01/2019 00:00
dt_hour = dt.hour_of_year() # should be something like that

Expected output: dt_hour = 48

It would be nice as well to obtain minutes_of_year and seconds_of_year

Answer 1

One way of implementing this yourself is this:

def hour_of_year(dt): 
    beginning_of_year = datetime.datetime(dt.year, 1, 1, tzinfo=dt.tzinfo)
    return (dt - beginning_of_year).total_seconds() // 3600

This first creates a new datetime object representing the beginning of the year. We then compute the time since the beginning of the year in seconds, divide by 3600 and take the integer part to get the full hours that have passed since the beginning of the year.

Note that using the days attribute of the timedelta object will only return the number of full days since the beginning of the year.

Answer 2

You can use timedelta:

import datetime
dt = datetime.datetime(2019, 1, 3, 00, 00, 00)
dt2 = datetime.datetime(2019, 1, 1, 00, 00, 00)
print((dt-dt2).days*24)

output:

48

Answer 3

All three functions, reusing their code.

import datetime

def minutes_of_year(dt):
    return seconds_of_year(dt) // 60

def hours_of_year(dt):
    return minutes_of_year(dt) // 60

def seconds_of_year(dt):
    dt0 = datetime.datetime(dt.year, 1, 1, tzinfo=dt.tzinfo)
    delta = dt-dt0
    return int(delta.total_seconds())

Edited to take possible time zone info into account.

Or: subclass datetime, for easier reuse in later projects:

import datetime

class MyDateTime(datetime.datetime):
    def __new__(cls, *args, **kwargs):
        return datetime.datetime.__new__(cls, *args, **kwargs)

    def minutes_of_year(self):
        return self.seconds_of_year() // 60

    def hours_of_year(self):
        return self.minutes_of_year() // 60

    def seconds_of_year(self):
        dt0 = datetime.datetime(self.year, 1, 1, tzinfo=self.tzinfo)
        delta = self-dt0
        return int(delta.total_seconds())

# create and use like a normal datetime object
dt = MyDateTime.now()
# properties and functions of datetime still available, of course.
print(dt.day)
# ... and new methods:
print(dt.hours_of_year())