How is time represented in python?

Python has a module named time to handle time-related tasks. To use functions defined in the module, we need to import the module first. Here's how:

import time

Here are commonly used time-related functions.

Python time.time[]

The time[] function returns the number of seconds passed since epoch.

For Unix system, January 1, 1970, 00:00:00 at UTC is epoch [the point where time begins].

import time
seconds = time.time[]
print["Seconds since epoch =", seconds]	

Python time.ctime[]

The time.ctime[] function takes seconds passed since epoch as an argument and returns a string representing local time.

import time

# seconds passed since epoch
seconds = 1545925769.9618232
local_time = time.ctime[seconds]
print["Local time:", local_time]	

If you run the program, the output will be something like:

Local time: Thu Dec 27 15:49:29 2018

Python time.sleep[]

The sleep[] function suspends [delays] execution of the current thread for the given number of seconds.

import time

print["This is printed immediately."]
time.sleep[2.4]
print["This is printed after 2.4 seconds."]

To learn more, visit: Python sleep[].

Before we talk about other time-related functions, let's explore time.struct_time class in brief.

time.struct_time Class

Several functions in the time module such as gmtime[], asctime[] etc. either take time.struct_time object as an argument or return it.

Here's an example of time.struct_time object.

time.struct_time[tm_year=2018, tm_mon=12, tm_mday=27, 
                    tm_hour=6, tm_min=35, tm_sec=17, 
                    tm_wday=3, tm_yday=361, tm_isdst=0]

The values [elements] of the time.struct_time object are accessible using both indices and attributes.

Python time.localtime[]

The localtime[] function takes the number of seconds passed since epoch as an argument and returns struct_time in local time.

import time

result = time.localtime[1545925769]
print["result:", result]
print["\nyear:", result.tm_year]
print["tm_hour:", result.tm_hour]

When you run the program, the output will be something like:

result: time.struct_time[tm_year=2018, tm_mon=12, tm_mday=27, tm_hour=15, tm_min=49, tm_sec=29, tm_wday=3, tm_yday=361, tm_isdst=0]

year: 2018
tm_hour: 15

If no argument or None is passed to localtime[], the value returned by time[] is used.

Python time.gmtime[]

The gmtime[] function takes the number of seconds passed since epoch as an argument and returns struct_time in UTC.

import time

result = time.gmtime[1545925769]
print["result:", result]
print["\nyear:", result.tm_year]
print["tm_hour:", result.tm_hour]

When you run the program, the output will be:

result = time.struct_time[tm_year=2018, tm_mon=12, tm_mday=28, tm_hour=8, tm_min=44, tm_sec=4, tm_wday=4, tm_yday=362, tm_isdst=0]

year = 2018
tm_hour = 8

If no argument or None is passed to gmtime[], the value returned by time[] is used.

Python time.mktime[]

The mktime[] function takes struct_time [or a tuple containing 9 elements corresponding to struct_time] as an argument and returns the seconds passed since epoch in local time. Basically, it's the inverse function of localtime[].

import time

t = [2018, 12, 28, 8, 44, 4, 4, 362, 0]

local_time = time.mktime[t]
print["Local time:", local_time]

The example below shows how mktime[] and localtime[] are related.

import time

seconds = 1545925769

# returns struct_time
t = time.localtime[seconds]
print["t1: ", t]

# returns seconds from struct_time
s = time.mktime[t]
print["\s:", seconds]

When you run the program, the output will be something like:

t1:  time.struct_time[tm_year=2018, tm_mon=12, tm_mday=27, tm_hour=15, tm_min=49, tm_sec=29, tm_wday=3, tm_yday=361, tm_isdst=0]

s: 1545925769.0

Python time.asctime[]

The asctime[] function takes struct_time [or a tuple containing 9 elements corresponding to struct_time] as an argument and returns a string representing it. Here's an example:

import time

t = [2018, 12, 28, 8, 44, 4, 4, 362, 0]

result = time.asctime[t]
print["Result:", result]

When you run the program, the output will be:

Result: Fri Dec 28 08:44:04 2018

Python time.strftime[]

The strftime[] function takes struct_time [or tuple corresponding to it] as an argument and returns a string representing it based on the format code used. For example,

import time

named_tuple = time.localtime[] # get struct_time
time_string = time.strftime["%m/%d/%Y, %H:%M:%S", named_tuple]

print[time_string]

When you run the program, the output will be something like:

12/28/2018, 09:47:41

Here, %Y, %m, %d, %H etc. are format codes.

• %Y - year [0001,..., 2018, 2019,..., 9999]
• %m - month [01, 02, ..., 11, 12]
• %d - day [01, 02, ..., 30, 31]
• %H - hour [00, 01, ..., 22, 23
• %M - minutes [00, 01, ..., 58, 59]
• %S - second [00, 01, ..., 58, 61]

To learn more, visit: time.strftime[].

Python time.strptime[]

The strptime[] function parses a string representing time and returns struct_time.

import time

time_string = "21 June, 2018"
result = time.strptime[time_string, "%d %B, %Y"]

print[result]

When you run the program, the output will be:

time.struct_time[tm_year=2018, tm_mon=6, tm_mday=21, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=3, tm_yday=172, tm_isdst=-1]

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