Question

I’ve been following a tutorial but keep getting the following error
AttributeError: Worm instance has no attribute 'move'
I’m not sure exactly what it means or how to fix it. The error refers to line 44 towards the bottom the line is w.move()(this one’s solved look below)

import pygame

class Worm:
    """A Worm."""
    def __init__(self, surface, x, y, length):
        self.surface = surface
        self.x = x
        self.y = y
        self.length = length
        self.dir_x = 0
        self.dir_y = -1
        self.body = []
        self.crashed = False

    def key_event(self, event):
        """Handle Key events that affect the worm."""
        if event.key == pygame.K_UP:
            self.dir_x = 0
            self.dir_y = -1
        elif event.key == pygame.K_DOWN:
            self.dir_x = 0
            self.dir_y = 1
        elif event.key == pygame.K_DOWN:
            self.dir_x = -1
            self.dir_y = 0
        elif event.key == pygame.K_DOWN:
            self.dir_x = 1
            self.dir_y = 0 
    def draw(self):
        for x, y in self.body:
            self.surface.set_at((x, y), (255, 255, 255))

width = 640
height = 400

screen = pygame.display.set_mode((width, height))
clock = pygame.time.Clock()
running = True

w = Worm(screen, width/2, height/2, 200)

while running:
    screen.fill((0, 0, 0))
    w.move()
    w.draw()

    if w.crashed or w.x <= 0 or w.x >= width -1 or w.y <= 0 or w.y >= height -1:
        print "crash"
        running = False

    for event in  pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN:
            w.key_event(event)

    pygame.display.flip()
    clock.tick(240)

———-Change ——–

code:

import pygame

class Worm:
    """A Worm."""
    def __init__(self, surface, x, y, length):
        self.surface = surface
        self.x = x
        self.y = y
        self.length = length
        self.dir_x = 0
        self.dir_y = -1
        self.body = []
        self.crashed = False

    def key_event(self, event):
        """Handle Key events that affect the worm."""
        if event.key == pygame.K_UP:
            self.dir_x = 0
            self.dir_y = -1
        elif event.key == pygame.K_DOWN:
            self.dir_x = 0
            self.dir_y = 1
        elif event.key == pygame.K_DOWN:
            self.dir_x = -1
            self.dir_y = 0
        elif event.key == pygame.K_DOWN:
            self.dir_x = 1
            self.dir_y = 0 
    def draw(self):
        for x, y in self.body:
            self.surface.set_at((x, y), (255, 255, 255))
    def move(self):
        """move worm."""
        self.x += self.vx
        self.y += self.vy

        if (self.x, sel.y) in self.body:
            self.crashed = True

        self.body.insert(0, (self.x, self.y))

        if len(self.body) > self.length:
            self.body.pop()

    def draw(self):
        #for x, y self.body:
        #    self.surface.set_at((x, y),self.color)
        x, y = self.body[0]
        self.surface.set_at((x, y), self.color)
        x, y = self.body[-1]
        self.surface.set_at((x, y), (0, 0, 0))


width = 640
height = 400

screen = pygame.display.set_mode((width, height))
clock = pygame.time.Clock()
running = True

w = Worm(screen, width/2, height/2, 200)

while running:
    screen.fill((0, 0, 0))
    w.move()
    w.draw()

    if w.crashed or w.x <= 0 or w.x >= width -1 or w.y <= 0 or w.y >= height -1:
        print "crash"
        running = False

    for event in  pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN:
            w.key_event(event)

    pygame.display.flip()
    clock.tick(240)

and Error –

Traceback (most recent call last):
  File "C:/Users/Enrique/Dropbox/Public/snakegametutorial.py", line 65, in <module>
    w.move()
  File "C:/Users/Enrique/Dropbox/Public/snakegametutorial.py", line 34, in move
    self.x += self.vx
AttributeError: Worm instance has no attribute 'vx'

Answer 1

AttributeError indicates that you attempted to access a property or method on an object that was not defined in the object’s class definition.

It just seems like you have not progressed far enough in the tutorial code to have defined the Worm.move() method. It occurs at line 43 of the tutorial, just before Worm.draw(). You are headed for another AttributeError on the draw() method, as you’ve not yet defined that one either. Just add both of these to the Worm class definition.

 43     def move(self):
 44         """ Move the worm. """
 45         self.x += self.vx
 46         self.y += self.vy
 47 
 48         if (self.x, self.y) in self.body:
 49             self.crashed = True
 50 
 51         self.body.insert(0, (self.x, self.y))
 52 
 53         if (self.grow_to > self.length):
 54             self.length += 1
 55 
 56         if len(self.body) > self.length:
 57             self.body.pop()
 58
 59     def draw(self):
 60         #for x, y in self.body:
 61         #    self.surface.set_at((x, y), self.color)
 62         x, y = self.body[0]
 63         self.surface.set_at((x, y), self.color)
 64         x, y = self.body[-1]
 65         self.surface.set_at((x, y), (0, 0, 0))

Update

You’re now receiving the AttributeError on Worm.vx because you’re missing that property (also vy) from Worm.__init__(). Compare your code to the code under the heading The improved game on the tutorial page. When you encounter further errors, compare your class definition to the tutorial’s.

Add to __init__()

def __init__(self, surface):
    ...
    ...
    self.vx = 0
    self.vy = -1
    ...
    ...