Python Coding challenge - Day 1302| What is the output of the following Python Code?

 

Code Explanation:

1. Defining a Generator Function

def process():

- Defines a function named process().

- This function contains yield statements, so Python treats it as a Generator Function.

- Unlike a normal function, a generator produces values one at a time instead of returning all values together.

2. First Yield Statement

    yield 10

- The yield keyword produces the value 10.

- The function pauses its execution at this point.

- Its current execution state is saved.

- When the generator is called again, execution resumes from where it stopped.

3. Second Yield Statement

    yield 20

- Produces the next value, which is 20.

- The generator pauses again.

- It remembers its current position and waits for the next request.

4. Return Statement

    return 30

- Ends the generator function.

- The value 30 is not yielded as a normal generator output.

- Instead, it becomes the value carried by the StopIteration exception.

- Once this statement executes, the generator is exhausted.

Important: yield produces values, whereas return terminates the generator.

5. Creating the Generator Object

g = process()

- Calls the generator function.

- Creates a generator object and stores it in g.

- The function body does not execute immediately.

- Execution starts only when we request a value using next().

6. Getting the First Value

print(next(g))

- next() starts executing the generator.

- Execution reaches yield 10.

- The generator pauses and returns 10.

- print() displays the value.

Output:

10

7. Getting the Second Value

print(next(g))

- Calls next() again on the same generator.

- Execution resumes after the first yield.

- It reaches yield 20.

- The generator pauses again and returns 20.

Output:

20

8. Handling Generator Exhaustion

print(next(g, "Finished"))

- Calls next() for the third time.

- The generator resumes after yield 20.

- It executes return 30 and terminates.

- Python raises StopIteration, carrying 30 as its value.

- However, next(g, "Finished") uses "Finished" as the default value when the generator is exhausted.

- Therefore, it prints "Finished" instead of raising an unhandled exception.

Output:

Finished

Final Output

Correct Answer

10

20

Finished

Book: 500 Days Python Coding Challenges with Explanation