Overview

A time object represents a (local) time of day, independent of any particular day

time object @python3 docs

Overview

A date object represents a date (year, month and day)

date object @python3 docs

Overview

A datetime object is a single object containing all the information from a date object and a time object.

datetime object @python3 docs

Overview

A timedelta object represents a duration, the difference between two dates or times.

timedelta object @python3 docs

Overview

An abstract base class. Capture information about the offset from UTC time, the time zone name, and whether Daylight Saving Time is in effect.

timedelta object @python3 docs

The dateutil module

dateutil module provides powerful extensions, good documentation and recent updates

Get current local and UTC datetimes

				import datetime

				# returns naive datetime object
				datetime_today = datetime.datetime.today()

				# equivalent to datetime.today(), when no tzinfo object is passed
				datetime_now = datetime.datetime.now()

				# returns the UTC time
				datetime_utc = datetime.datetime.utcnow()

				print(datetime_today)
				print(datetime_now)
				print(datetime_utc)

				#2018-04-18 18:04:11.148224
				#2018-04-18 18:04:11.148232
				#2018-04-18 15:04:11.148234
			

Get current date and time

				import datetime

				# get current date
				date_now = datetime.date.today()
				# or:
				# date_now = datetime.datetime.today().date()
				print("Current date: ",date_now)

				# get current time
				time_now = datetime.datetime.today().time()
				print("Current time: ",time_now)

				#Current date:  2018-04-18
				#Current time:  17:59:19.556068
			

Format datetime object as string

Check strftime() and strptime() Behavior, where are published all formatting codes supported by Python

				import datetime

				# get the date object
				today = datetime.datetime.today()

				# now, format it as string, using the format codes:
				print("Year:", today.strftime("%Y"))
				print("Month:", today.strftime("%m"))
				print("Day:", today.strftime("%d"))
				print("Hour:", today.strftime("%H"))
				print("Minutes:", today.strftime("%M"))
				print("Seconds:", today.strftime("%s"))
			

Create datetime object from string

				import datetime

				dt = datetime.datetime.strptime("15/02/17 22:10", "%d/%m/%y %H:%M")
				print(dt)
				# 2017-02-15 22:10:00

				bdate = datetime.datetime.strptime("18.12.31", "%y.%m.%d")
				print(bdate)
				# 2018-12-31 00:00:00
			

Calculate time interval

				from datetime import datetime

				t1 = datetime.strptime("08:30", "%H:%M")
				t2 = datetime.strptime("12:15", "%H:%M")
				print(t2 - t1)

				#3:45:00
			

Timing your code

For better precision (to account only the CPU time of your process ) use Python profilers built-in modules

				import time
				from functools import reduce

				#start timer
				start = time.time()

				# do some time intensive stuff:
				sum = reduce(lambda x,y:x+y, range(1,1_000_001))
				print("The sum of numbers from 1 to 1_000_000 is: ", sum)

				#end timer
				end = time.time()

				print("[Finished in {:.6f}s]".format(end - start))

				#The sum of numbers from 1 to 1_000_000 is:  500000500000
				#[Finished in 0.087371s]
			

Get weekday name for given date

			import datetime

			def get_weekday_name(date):
				named_wd = ["понеделник", "вторник", "сряда", "четвъртък", "петък", "събота", "неделя"]

				wd_name = named_wd[date.weekday()]
				return wd_name

			date = datetime.datetime.strptime("06/04/18", "%d/%m/%y")
			print( get_weekday_name(date) )
			#петък
		

When will my birthday be on Sunday?

			import datetime

			def get_next_sunday_date(bdate, period):
				"""get_next_sunday_date

				Args:
				    bdate (datetime): Object representing the date
				    period (tuple): (start_year,end_year) interval to look into

				Returns:
				    list: years, on which a date will be on Sunday
				"""
				years = []

				for y in range(*period):
					bdate_weekday = datetime.date(y, bdate.month, bdate.day).weekday()

					if bdate_weekday == 6:
						years.append(y)

				return years


			birth_date = datetime.datetime.strptime("31/12/00", "%d/%m/%y")

			sundays_years = get_next_sunday_date(birth_date, (2018,2100))
			print(sundays_years)
			#[2023, 2028, 2034, 2045, 2051, 2056, 2062, 2073, 2079, 2084, 2090]
		

Calculates the Western Easter date for given period

Using the Samuel Butcher Algorithm, published in Computus @ wikipedia.

			import datetime

			def butcher_easter(year):
			    "Returns Easter as a date object."
			    a = year % 19
			    b = year // 100
			    c = year % 100
			    d = (19 * a + b - b // 4 - ((b - (b + 8) // 25 + 1) // 3) + 15) % 30
			    e = (32 + 2 * (b % 4) + 2 * (c // 4) - d - (c % 4)) % 7
			    f = d + e - 7 * ((a + 11 * d + 22 * e) // 451) + 114
			    month = f // 31
			    day = f % 31 + 1
			    return datetime.date(year, month, day)

			def easter_dates_between(start, end):
			    for year in range(start, end+1):
			        print( butcher_easter(year).strftime("%d.%m.%Y") )


			easter_dates_between(2018, 2050)
		

The dateutil modules provides easter.py module, supporting Western, Ortodox and Julian Calendars.

The Task

Write a function, that calculates the remaining days from current date to your next birthday day.

The output should be only the number of days.

Hint

To calculate difference between two date objects, t1 and t2, you can use: t1-t2 which will return a timedelta Object