Mastering the Art of Programming in Python 3/

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Challenge: Time My Functions

Challenge: Time My Functions

Time my functions with meta-programming.

We'll cover the following...

Problem statement

In this exercise, we want to time our functions. What we want is that whenever a class method executes, it should print the time taken by itself.

Let’s get into detail. Consider the scenario below while attempting the challenge.

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We have an Animal class. It has a function talk as follows:

class Animal():

    def talk(self):
        time.sleep(1)
        print("Animal talk")

And, we have a decorator time_taken that calculates the required time taken by any function.

Now, if we want to calculate the time for talk, we can simply add @time_taken before its header, and the problem is solved!

But what if we create child classes of Animal in the future and want to decorate all the functions of child classes? Adding @time_taken at the beginning of every definition would be time-taking and hectic.

To avoid such a repetitive fuss, if we know beforehand that every subclass must have this timing property, then we should look up to metaclass based solution.

So, the challenge is that when the classes are created, they should be immediately wrapped up by a timing method decorator. The solution requires three steps:

  • Create a metaclass TimeMeta feeding class object to the class decorator method

  • Create a class decorator method timeit that makes use of time_taken decorator to debug class methods.

  • Create time_taken decorator that times the passed method by keeping track of start time and end time.

Try to solve the problem below. Do not forget to use the concepts taught in the previous lessons. Feel free to view the solution in the next lesson, after giving it a few shots. Good luck!

Python 3.10.4
import time
# Decorator for timing the passed functions
def time_taken(func):
  # Implement your function here
  pass
# Class decorator making use of time_taken decorator to debug class methods
def timeit(cls): 
  # Implement your function here
  pass
''' Metaclass feeding created class object to timeit method to get timing
 functionality enabled objects '''
class TimeMeta(type):
  # Implement your class here
  pass
''' Base class with metaclass TimeMeta, now all the subclass of this  
will have timing applied '''
class Animal(metaclass=TimeMeta):
    def talk(self):
        time.sleep(1)
        print("Animal talk")
class Cow(Animal):
    def talk(self):
        time.sleep(1)
        print("Moo")
class Dog(Animal):
    def talk(self):
        time.sleep(1)
        print("Bark")
# Testing the code
animal = Animal()
cow = Cow()
dog = Dog()
print(animal.talk())
print(cow.talk())
print(dog.talk())

We hope that you were able to solve the challenge.

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