Final Practice — Build a User Store

Estimated time: ~1–2 hours. 🧪 Don't watch videos for this part.

After studying Phases 1–8, close everything else and build this from memory, looking things up only when you get stuck. If you copy the finished code below without typing it yourself, you skip the part that actually makes it stick.

Tomorrow, you'll basically turn these exact functions into FastAPI HTTP endpoints — so getting comfortable writing them now is real prep, not busywork.

The store

A single in-memory list, just like the nested-data example from Phase 2:

users = []

Given — study these two first

These two are worked examples. Read them, understand why they're written this way, then close this page before attempting the rest.

def add_user(name: str, email: str):
    user = {
        "id": len(users) + 1,
        "name": name,
        "email": email,
        "active": True
    }

    users.append(user)
    return user

def get_user(user_id: int):
    for user in users:
        if user["id"] == user_id:
            return user

    return None

Notice what these two are already using from earlier phases: type hints (Phase 3 & 7), a dict as a "record" (Phase 2), and for + if to search a list by hand (Phase 1 & 2).

Your turn

Implement these five yourself. Each one below is a spec — the signature and exactly what it should do — not the code. Write the body before looking at the solution at the bottom.

1. Get all users

def get_all_users():
    ...

Return every user in the store.

2. Update user

def update_user(user_id: int, name: str | None = None, email: str | None = None):
    ...

Find the user by user_id. Update name and/or email only if a new value was actually passed in — leave a field untouched if its argument is None. Return the updated user, or None if no user with that id exists.

3. Delete user

def delete_user(user_id: int):
    ...

Remove the user with that id from users. Return True if a user was deleted, False if no user with that id existed.

4. Search users

def search_users(query: str):
    ...

Return every user whose name contains query (case-insensitive).

5. Filter active users

def filter_active_users():
    ...

Return only the users where active is True.

def get_all_users():
    return users


def update_user(user_id: int, name: str | None = None, email: str | None = None):
    user = get_user(user_id)

    if user is None:
        return None

    if name is not None:
        user["name"] = name
    if email is not None:
        user["email"] = email

    return user


def delete_user(user_id: int):
    user = get_user(user_id)

    if user is None:
        return False

    users.remove(user)
    return True


def search_users(query: str):
    return [user for user in users if query.lower() in user["name"].lower()]


def filter_active_users():
    return [user for user in users if user["active"]]

Where this goes tomorrow

Each function here becomes one FastAPI route — same logic, wrapped in an endpoint:

add_user             → POST   /users
get_all_users        → GET    /users
get_user             → GET    /users/{user_id}
update_user          → PUT    /users/{user_id}
delete_user          → DELETE /users/{user_id}
search_users         → GET    /users/search?q=...
filter_active_users  → GET    /users/active