03_loops.py

"""
Short examples demonstrating Python loops (for / while) and iteration patterns.

This module includes:
- count_up: a simple for-loop counting from 1 to a target number.
- countdown: a while-loop that decrements until reaching zero.
- iterate_habits: iterating through a list with indexes and friendly output.
"""

from typing import List


def count_up(to_number: int) -> List[int]:
    """Return a list counting upward from 1 through to_number."""
    return [i for i in range(1, to_number + 1)]


def countdown(start: int) -> List[int]:
    """Return a list counting down from `start` to 1 using a while-loop."""
    numbers = []
    current = start

    while current > 0:
        numbers.append(current)
        current -= 1

    return numbers


def iterate_habits(habits: List[str]) -> List[str]:
    """Return a formatted list describing habits with their index positions."""
    return [f"{index + 1}. {habit}" for index, habit in enumerate(habits)]


def main() -> None:
    print("Counting up to 5:")
    print(count_up(5))

    print("\nCountdown from 5:")
    print(countdown(5))

    print("\nHabits list:")
    habits = ["Workout", "Code", "Read", "Stretch"]
    for line in iterate_habits(habits):
        print(line)


if __name__ == "__main__":
    main()