重温python，为什么这不抛出ValueError？

Question

I'm brushing up on my python. I've been coding in java for a year, but I'm about to take an algorithms class in Python. In preparation, I am duplicating the Lights Out puzzle game as a personal practice. I've written the first logic for the light object, and I've designed it to throw an error when I construct a Light() with a negative 0 value, but it won't throw an exception no matter what I construct the object with.

For example: light Light(1,1) is valid, but light Light(-1,-1) should throw a ValueError. Where am I going wrong?

# Light.py represents a light object for LightsOut game.
# written by nrsmac

class Light:
    # Light.py represents a light object for LightsOut game.
    # written by nrsmac

    #Constants for Light States
    OFF = 0
    ON  = 1

    #Each light has a positive x and y position, negative 1 by defailt
    x = -1
    y = -1

    currentState = OFF

    #Constructor here
    def __init__(self, x, y):
        self.x = x
        self.y = y

        if self.isValidLocation() == False:
            raise ValueError('Invalid Location!')

    def toggle(self): # TODO: Make this change color
        if self.currentState == self.ON:
            self.currentState = self.OFF
        elif self.currentState == self.OFF:
            self.currentState = self.ON

    def printCurrentLightState(self):
        print(self.currentState)

    def getX(self):
        return self.x

    def getY(self):
        return self.y

    def setLightState(self, state):
        self.currentState = state

    def isValidLocation(self):
        if self.x < 0 | self.y < 0:
            return False

Does python always have this many self calls? It's starting to get exhausting from a Java perspective.

Answer 1

I think that in your case the usage of | is not correct. You have to use or , like so:

if (self.x < 0) or (self.y < 0):

Answer 2

Basic getters/setters like that aren't a thing in Python.

Having to type self over and over again is indeed annoying. However, we also have IDEs and text editors which support autocompletion, so it shouldn't be a massive issue.

---

This is what I would do to make the code more pythonic:

@dataclass(init=False)
class Light:
    x: int
    y: int
    is_on: bool

    def __init__(self, x: int, y: int, is_on: bool = False) -> None:
        if x < 0 or y < 0:
            raise ValueError(f'Invalid location arguments in Light constructor: {x}, {y}')
        else:
            self.x = x
            self.y = y
            self.is_on = is_on

    def toggle(self) -> None:
        self.is_on = not self.is_on 

It's a work in progress, I think it can still be improved.