Python Expert · Lesson 1 · On the house

Generators

yield — one value at a time. Lesson 1 is free — on the house.

Lessons · Python Expert · Lesson 1 of 10 · On the house

Generators

yield — one value at a time.

Illustration for the Python course — Lesson 1 is on the house. The rest opens with the paper, the Daily, or a gift.

This is Python · expert, lesson 1: Generators. Read the teaching and the stills before the checks. The quizzes are open book and test the subject — Python itself — not product rules or layout trivia.

yield turns a function into a generator.

list(count(3)) materializes [0,1,2].

Generators save memory; they are single-pass.

for-loops handle StopIteration.

gen

def count(n):
    i = 0
    while i < n:
        yield i
        i += 1

print(list(count(3)))

Match this when you type. Open book.

Sit with that still. Trace it top to bottom. Name each piece. The exercise asks you to match its essence.

If something fails when you try it yourself, change one thing. Read the error. Return to the still. I will not rush you.

Quiz

What does yield do?

Produces a value and suspends the generator
Returns permanently like return only
Deletes the function
Starts asyncio

Quiz

What is list(count(3))?

[0, 1, 2]
[1, 2, 3]
[3]
[]

Quiz

Are generators multi-pass by default?

No — exhausted after one pass
Yes — infinitely reusable
Only if frozen
Only for strings

Quiz

Based on today's teaching, which claim is right?

Suspend and produce.
The opposite of what the lesson said
The lesson forbade this topic
None of the subject material applies

Quiz

Based on today's teaching, which claim is right?

0..n-1.
The opposite of what the lesson said
The lesson forbade this topic
None of the subject material applies

Quiz

Based on today's teaching, which claim is right?

Single-pass.
The opposite of what the lesson said
The lesson forbade this topic
None of the subject material applies

Check

Match the still for: Generators.

That is the lesson. When every quiz and exercise on this page is green, mark it passed. Next lesson when you are ready.

Open-book: the answers are on this page. Pass every quiz and check (7) to mark the lesson done. This visit: 0/7.

Generators · Python Expert (free) — The Gold Standard