Book Image

Learning Python

By : Romano
Book Image

Learning Python

By: Romano

Overview of this book

Learning Python has a dynamic and varied nature. It reads easily and lays a good foundation for those who are interested in digging deeper. It has a practical and example-oriented approach through which both the introductory and the advanced topics are explained. Starting with the fundamentals of programming and Python, it ends by exploring very different topics, like GUIs, web apps and data science. The book takes you all the way to creating a fully fledged application. The book begins by exploring the essentials of programming, data structures and teaches you how to manipulate them. It then moves on to controlling the flow of a program and writing reusable and error proof code. You will then explore different programming paradigms that will allow you to find the best approach to any situation, and also learn how to perform performance optimization as well as effective debugging. Throughout, the book steers you through the various types of applications, and it concludes with a complete mini website built upon all the concepts that you learned.
Table of Contents (14 chapters)
13
Index

Decorators


In the previous chapter, I measured the execution time of various expressions. If you recall, I had to initialize a variable to the start time, and subtract it from the current time after execution in order to calculate the elapsed time. I also printed it on the console after each measurement. That was very tedious.

Every time you find yourself repeating things, an alarm bell should go off. Can you put that code in a function and avoid repetition? The answer most of the time is yes, so let's look at an example.

decorators/time.measure.start.py

from time import sleep, time

def f():
    sleep(.3)

def g():
    sleep(.5)

t = time()
f()
print('f took: ', time() - t)  # f took: 0.3003859519958496

t = time()
g()
print('g took:', time() - t)  # g took: 0.5005719661712646

In the preceding code, I defined two functions, f and g, which do nothing but sleep (by 0.3 and 0.5 seconds respectively). I used the sleep function to suspend the execution for the desired amount of time. I also highlighted...