dicts.py

"""Functions to keep track and alter inventory."""

ItemsType = list[str, ...]
InventoryType = dict[str, int]


def create_inventory(items: ItemsType) -> InventoryType:
    """Create a dict that tracks the amount (count) of each element on the `items` list.

    :param items: list - list of items to create an inventory from.
    :return: dict - the inventory dictionary.
    """
    return add_items({}, items)


def add_items(inventory: InventoryType, items: ItemsType) -> InventoryType:
    """Add or increment items in inventory using elements from the items `list`.

    :param inventory: dict - dictionary of existing inventory.
    :param items: list - list of items to update the inventory with.
    :return: dict - the inventory updated with the new items.
    """
    for item in items:
        inventory[item] = inventory.get(item, 0) + 1
    return inventory


def decrement_items(inventory: InventoryType, items: ItemsType) -> InventoryType:
    """Decrement items in inventory using elements from the `items` list.

    :param inventory: dict - inventory dictionary.
    :param items: list - list of items to decrement from the inventory.
    :return: dict - updated inventory with items decremented.
    """
    for item in items:
        if inventory[item] > 0:
            inventory[item] -= 1
    return inventory


def remove_item(inventory: InventoryType, item: str) -> InventoryType:
    """Remove item from inventory if it matches `item` string.

    :param inventory: dict - inventory dictionary.
    :param item: str - item to remove from the inventory.
    :return: dict - updated inventory with item removed. Current inventory if item does not match.
    """
    updated_inventory = inventory.copy()
    updated_inventory.pop(item, None)
    return updated_inventory


def list_inventory(inventory: InventoryType) -> list[tuple[str, int], ...]:
    """Create a list containing all (item_name, item_count) pairs in inventory.

    :param inventory: dict - an inventory dictionary.
    :return: list of tuples - list of key, value pairs from the inventory dictionary.
    """
    return [(item, value) for item, value in inventory.items() if value > 0]