Importing and Using the Python Time Module

Preparing to work with Python time

To be able to work with time in Python, you need to first import the module:

import time

Python time module allows you to work with all time-related functions. Most of them simply call the platform C library functions that have the same name. However, there might be small differences between different platforms. The time module is available in all versions of Python.

Understanding time in Python: the epoch

The most basic function in the Python time module is time():

seconds = time.time()
print("It's", seconds, "seconds since the epoch.")

It returns a floating point value that represents the number of seconds that have passed since the epoch. The epoch is a a platform-dependent point where the time starts.

If you're unsure what is the epoch on the system you're using, use the gmtime() function. It takes one argument (a number of seconds) and converts the time to a struct. If you define the number as zero, it will simply display the beginning of the epoch:

print(time.gmtime(0))

Converting Python time

The gmtime() function returns the struct time in Coordinated Universal Time (UTC). If you need it in local time, use localtime(). To get an opposite result, use mktime():

t = time.localtime(seconds)
print("The struct_time is:", t)

sec = time.mktime(t)
print("The number of seconds is:", sec)

If you need the Python time represented in a string, use asctime() (if you have a struct time) or cttime() (if you have a floating point value). Both of these functions will return a Python timestamp:

t = (2020, 1, 13, 13, 18, 9, 0, 3, 0)
date = time.asctime(t)

seconds = time.time()
date2 = time.ctime(seconds)

Using the Python time.sleep() function

The time module also allows you to time the execution of your threads. To delay a certain process, use the Python time.sleep() function:

print("Hello.")
time.sleep(3)
print("It's been three seconds since we said hello.")

You only need to define one argument, which is a floating-point number. It represents the number of seconds to delay the action for.

Using the Python time.sleep() function with a while loop, you can also create a basic digital clock:

while True:
  localtime = time.localtime()
  result = time.strftime("%I:%M:%S", localtime)
  print(result)
  time.sleep(1)

Python time: useful tips

• There are two more Python modules that help you deal with time and date: calendar handles the calendar-related functions, and datetime lets you manipulate Python timestamps. You can also extend datetime withe the dateutil package from PyPI.
• If you're working with multithreaded programs, remember that the Python time.sleep() function only delays a single thread and not the whole process.