I'm building a small Python escape game with several rooms. The player can move east or west, pick up a golden key in room 2, and drop it in another room. However, after entering commands like "e, e, get key, e, drop key," the debug output still shows the key in room 2, and the game does not report that a golden key is lying on the floor in room 3. I suspect the problem is in the function that updates the key's location. I'd also appreciate advice for finding and preventing logic errors like this.
3 Answers
A debugger or more targeted debug output can make this much easier to spot. Print the command, player position, key location, and `got_key` immediately before and after each action. You can also use a linter or editor warning that detects suspicious expressions such as a comparison whose result is ignored. For a larger game, dictionaries or small `Player` and `Key` classes could make the state easier to manage, but fixing the assignment operator is the immediate issue.
You may not need to update `key_location` every turn while the player is carrying the key. A simpler model is to treat the key as being either in a room or in the player’s inventory. When the player picks it up, set `got_key` to `True`; when they drop it, set `got_key` to `False` and set `key_location = player_position`. Right now, `drop key` only changes the inventory flag, so the key’s room never gets updated when it is dropped.
The main bug is in `check_n_update_key()`. You wrote `key_location == player_position`, which compares the two values but does not change anything. Use assignment instead: `key_location = player_position`. You’ll also need to return the updated value, for example: `def check_n_update_key(player_position, got_key, key_location):n if got_key:n key_location = player_positionn return key_location`.
That was it—thank you! I completely missed the difference.
That’s the classic comparison-versus-assignment mistake: `==` asks whether two values are equal, while `=` stores a new value.