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Python

Posted by Rastko Jovic
Rastko Jovic
14,883 Points

random.choice(MAP) sometimes returns NoneType

There seems to be a problem while trying to take a random value from MAP. http://pastebin.com/5W6vjawH

Chris Freeman
Chris Freeman
Treehouse Moderator 68,468 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,468 Points

Can you explain why you assert this? Is an error raised? or is it perhaps the value of player, monster, or door happen to be NoneType? Which is not the same thing as random.choice() being the cause.

Rastko Jovic
Rastko Jovic
14,883 Points

It doesn't always happen but sometimes randomly when i start the game it does and that's why i assume it has something to do with random.choice(). An exception is raised and only the player is NoneType, but both the door and the monster variable's values are assigned properly.

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,468 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,468 Points

I was able to reproduce the error. In the function start_position at ①, if player, monster, or door have the same value, start_position() is called but the return values are not captured at ②. The function then ends and a None is returned. Fix by returning the values at ②.

def start_position():
    player = random.choice(MAP)
    monster = random.choice(MAP)
    door = random.choice(MAP)

    # check to see if they occupy the same space
    if player == monster or door == monster or door == player:  # ①
        start_position()  # ②
    else:
        return player, monster, door
Rastko Jovic
Rastko Jovic
14,883 Points

Thank you sir!