Iteration Patterns

Map, filter, reduce as common loop shapes.

Lesson 3

Concept

Many tasks fit patterns: map transforms each item; filter keeps some items; reduce folds many values into one. Prefer built-ins where idiomatic.

Try it

Order the steps to filter even numbers

These steps are out of order — can you fix them?

1.Check if divisible by 2
2.Iterate items
3.Return result list
4.Keep passing items