Python: Why Does a Method Behave Differently with an Added Parameter?
- by SteveStifler
I have a method in a Pygame Sprite subclass, defined as such:
def walk(self):
"""move across screen"""
displacement = self.rect.move((self.move, 0))
if self.rect.left < self.area.left or self.rect.right > self.area.right:
self.move = -self.move
displacement = self.rect.move((self.move, 0))
self.rect = displacement
I modified it, adding a parameter speed_x, and now the program is broken.
def walk(self, speed_x):
"""move across screen"""
displacement = self.rect.move((speed_x, 0))
if self.rect.left < self.area.left or self.rect.right > self.area.right:
speed_x = -speed_x
displacement = self.rect.move((speed_x, 0))
self.rect = displacement
Before I called the method like this:
def update(self):
self.walk()
Now I do:
def update(self):
self.walk(self.move)
Why doesn't this work?
