Python3 Date and Time

Python programs can handle date and time in many ways. Converting date formats is a common functionality.

Python provides the time and calendar modules to help format dates and times.

Time intervals are floating-point numbers in units of seconds.

Each timestamp represents the time elapsed since midnight (the epoch) of January 1, 1970.

The Python time module provides many functions to convert common date formats. For example, the function time.time() is used to get the current timestamp, as shown in the following example:

Example

#!/usr/bin/python3

import time  # Import the time module

ticks = time.time()

print("Current timestamp:", ticks)

The output of the above example is:

Current timestamp: 1459996086.7115328

Timestamps are best suited for date arithmetic. However, dates before 1970 cannot be represented this way. Very distant dates are also not supported; UNIX and Windows only support up to the year 2038.

What is a Time Tuple?

Many Python functions use a time tuple, which is a tuple of 9 numbers, to handle time:

The above is also known as a struct_time tuple. This structure has the following attributes:

Getting the Current Time

To convert a timestamp (a floating-point number) to a time tuple, simply pass the floating-point number to a function like localtime.

#!/usr/bin/python3
import time

localtime = time.localtime(time.time())
print("Local time:", localtime)

The output of the above example is:

Local time: time.struct_time(tm_year=2016, tm_mon=4, tm_mday=7, tm_hour=10, tm_min=28, tm_sec=49, tm_wday=3, tm_yday=98, tm_isdst=0)

Getting Formatted Time

You can choose from various formats according to your needs, but the simplest function to get a readable time string is asctime():

#!/usr/bin/python3
import time

localtime = time.asctime(time.localtime(time.time()))
print("Local time:", localtime)

The output of the above example is:

Local time: Thu Apr 7 10:29:13 2016

Formatting Dates

We can use the strftime method of the time module to format dates:

time.strftime(format[, t])

Example

#!/usr/bin/python3

import time

# Format as 2016-03-20 11:45:39
print(time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()))

# Format as Sat Mar 28 22:24:24 2016
print(time.strftime("%a %b %d %H:%M:%S %Y", time.localtime()))

# Convert format string to timestamp
a = "Sat Mar 28 22:24:24 2016"
print(time.mktime(time.strptime(a, "%a %b %d %H:%M:%S %Y")))

The output of the above example is:

2016-04-07 10:29:46
Thu Apr 07 10:29:46 2016
1459175064.0

Python date and time formatting symbols:

• %y Two-digit year representation (00-99)
• %Y Four-digit year representation (0000-9999)
• %m Month (01-12)
• %d Day of the month (0-31)
• %H Hour (24-hour clock) (0-23)
• %I Hour (12-hour clock) (01-12)
• %M Minute (00-59)
• %S Second (00-59)
• %a Local abbreviated weekday name
• %A Local full weekday name
• %b Local abbreviated month name
• %B Local full month name
• %c Local appropriate date and time representation
• %j Day of the year (001-366)
• %p Local equivalent of A.M. or P.M.
• %U Week number of the year (00-53), where Sunday is the first day of the week
• %w Weekday (0-6), where Sunday is the first day of the week
• %W Week number of the year (00-53), where Monday is the first day of the week
• %x Local appropriate date representation
• %X Local appropriate time representation
• %Z Current time zone name
• %% Literal '%' character

Getting a Month's Calendar

The calendar module has extensive methods for handling year and month calendars, such as printing the calendar for a specific month:

Example

#!/usr/bin/python3

import calendar

cal = calendar.month(2016, 1)
print("Here is the calendar for January 2016:")
print(cal)

The output of the above example is:

Here is the calendar for January 2016:
January 2016
Mo Tu We Th Fr Sa Su
 1  2  3  4  5  6  7
 8  9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31

The Time Module

The time module contains the following built-in functions, including those for time processing and time format conversion:

>>> import time
>>> print("time.altzone %d " % time.altzone)
time.altzone -28800

>>> import time
>>> t = time.localtime()
>>> print("time.asctime(t): %s " % time.asctime(t))
time.asctime(t): Thu Apr 7 10:36:20 2016

>>> import time
>>> print("time.ctime() : %s" % time.ctime())
time.ctime() : Thu Apr 7 10:51:58 2016

>>> import time
>>> print("gmtime :", time.gmtime(1455508609.34375))
gmtime : time.struct_time(tm_year=2016, tm_mon=2, tm_mday=15, tm_hour=3, tm_min=56, tm_sec=49, tm_wday=0, tm_yday=46, tm_isdst=0)

>>> import time
>>> print("localtime(): ", time.localtime(1455508609.34375))
localtime(): time.struct_time(tm_year=2016, tm_mon=2, tm_mday=15, tm_hour=11, tm_min=56, tm_sec=49, tm_wday=0, tm_yday=46, tm_isdst=0)

#!/usr/bin/python3
import time

print("Start : %s" % time.ctime())
time.sleep(5)
print("End : %s" % time.ctime())

>>> import time
>>> print(time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()))
2016-04-07 11:18:05

>>> import time
>>> struct_time = time.strptime("30 Nov 00", "%d %b %y")
>>> print("Returned tuple: ", struct_time)
Returned tuple: time.struct_time(tm_year=2000, tm_mon=11, tm_mday=30, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=335, tm_isdst=-1)

>>> import time
>>> print(time.time())
1459999336.1963577

The time module contains the following two very important attributes:

The Calendar Module

The functions in this module are related to calendars, such as printing the character calendar for a specific month.

Monday is the default first day of the week, and Sunday is the default last day. To change this setting, call the calendar.setfirstweekday() function. The module contains the following built-in functions:

>>> import calendar
>>> print(calendar.isleap(2000))
True
>>> print(calendar.isleap(1900))
False

>>> import calendar
>>> calendar.monthrange(2014, 11)
(5, 30)

Other Related Modules and Functions

In Python, other modules for handling date and time include:

• time module
• datetime module