Exploring Python’s Yield Keyword: A Beginner’s Guide to Lazy Evaluation

Learn how the ‘yield’ keyword transforms functions into generators, enabling efficient memory usage and simplified code in Python

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Python’s ‘yield’ keyword is a powerful tool that can transform ordinary functions into generators, unlocking a world of possibilities for efficient programming. In this article, we’ll explore the ins and outs of ‘yield’, demystifying its usage and demonstrating its practical applications.

Understanding the Basics

At its core, the ‘yield’ keyword allows a function to pause its execution and yield a value to the caller. Unlike ‘return’, which terminates the function and returns a single value, ‘yield’ enables the function to produce a sequence of values, one at a time.

Transforming Functions into Generators

To turn a function into a generator, simply replace ‘return’ with ‘yield’. Let’s illustrate this with a simple example:

def countdown(n):
    while n > 0:
        yield n
        n -= 1

# Using the generator
for i in countdown(5):
    print(i)