17. datetime

Question 1

covert second to readable format, or vice versa

Answer 1

system time is stored as timestamp (i.e. second)

1. time.ctime -> str
2. dtobj
   datetime. fromtimestamp(dtobj)

to revert
3.dtobj.timestamp()

Question 2

get current time

Answer 2

now = datetime.now()

Question 3

timedelta object

Answer 3

year = timedelta(days = 365)

Question 4

create datetime object

Answer 4

datetime(2020, 5, 17)\
datetime(2020, 5, 17,12,30,30)
must be integer

Question 5

print time format

Answer 5

dtobj.strftime ** f for format

Convert object to a string according to a given format

Question 6

from str to datetime

Answer 6

datetime.strptime(str)

Parse a string into a datetime object given a corresponding format

Question 7

import datetime

Answer 7

if you don’t want to repeat too many datetime
use
from datetime import datetime, timedelta

Question 8

count run time (timeit)

Answer 8

Your statements here

import timeit ** in second, and not in datetime module

start = timeit.default_timer()

stop = timeit.default_timer()

print(‘Time: ‘, stop - start)

Question 9

timeit can actually run it over and over again

Answer 9

note stmt and setup are both block string
setup will only run one, i.e. defining the function
stmt is the stmt ran multiple times, i.e. calling the function

timeit.timeit(stmt, setup, number = 10000)

%%timeit (for jupyter magic keyword)
myfunction