调用类实例时出错

Question

我在 Python 2.7 中使用 Pygame 制作的这个程序。这是我第一次尝试使用类创建游戏。我正在尝试使用英雄的统计信息初始化一个类，例如名为“弓箭手”的 hp、速度等。当我尝试运行代码时，它给了我这个错误：

Traceback (most recent call last): File "C:/Python27/rpg.py", line 85, in <module> archer.walk() NameError: name 'archer' is not defined

这是我的代码。

from pygame import *
from random import *
from time import *
import pygame
init()
###############VARIABLES
xmove = 0
ymove = 0
white = ( 255,255,255 )

###############INITIALIZING
def preStuff():
    heroSelect()#choose a hero
    initiateScreen()#set screen size
def initiateScreen():
    screen = display.set_mode ((500,500))
def heroSelect():
    print """ Welcome to Boss Fights!
Select a hero:
Archer: Use a bow for long range attacks! Attacks do little damage, but can hit from far away. Has average health.

Warrior: Smite enemies with his powerful sword! Attacks a very powerful, but have very short range and are quite slow. Has high health.

Assasin: Hit your enemy without them even seeing you! Assasin moves very quickly, and attacks quickly Has low health.

Alien: Blast your enemy with fire! Use a staff to shoot strong fireballs at enemies, with moderate damage and range. Has average health.


"""
    heroC = raw_input('Which class would you like?')
    if heroC == 'Archer' or 'archer' or 'ar':
        archer=Hero(50,250,image.load('archer.png'),100,.3,.1)#initialize Hero as: archer
    elif heroC == 'Warrior' or 'warrior' or 'w':
        warrior=Hero(50,250,image.load('warrior.png'),200,.4,.05)
    elif heroC == 'Assasin' or 'assasin' or 'as':
        assasin=Hero(50,250,image.load('asassin.png'),125,.1,.2)
    elif heroC == 'Alien' or 'alien' or 'al':
        alien=Hero(50,250,image.load('alien.png'),150,.3,.1)



class Hero:    
    def __init__(self,x,y, blitImg,hp,attackspeed,speed):
        self.x=x
        self.y=y
        self.blitImg=blitImg
        self.hp = hp
        self.attackspeed = attackspeed
        self.speed=speed

def walk(self):

    for event in pygame.event.get():
        if event.type==QUIT:
            pygame.quit()
            sys.exit()            
        if event.type == KEYDOWN:
            if event.key == K_s:
                ymove = self.speed
            elif event.key == K_w:
                ymove = -self.speed
            elif event.key == K_a:
                xmove = -self.speed
            elif event.key == K_d:
                xmove = self.speed
        elif event.type == KEYUP:
            if event.key == K_a or K_s or K_d or K_w:
                xmove = 0
                ymove = 0
    self.y += ymove
    self.x += xmove
    screen.fill( white )
    screen.blit(self.blitImg,(self.x,self.y))
    display.update()






if __name__ == "__main__":
    preStuff()
    while True:
        archer.walk()

我现在只是想让角色走路。（只是弓箭手类） 我试过跑步

archer=Hero(50,250,image.load('archer.png'),100,.3,.1)

在外壳中，它工作正常。我可以调用 archer.y 和其他变量，它们打印得很好。请有人帮我弄清楚为什么这不起作用！ （P.S.我是一个初学者程序员，所以如果它是一些简单、容易的修复，我太笨了，请原谅） 谢谢！

Answer 1

archer 是一个局部变量，因此在程序最后一行正在运行的全局范围内是不可见的。您可能想让 heroSelect() 返回创建的 Hero 对象，然后让 preStuff() 方法也返回它。