作为新程序员避免在Python中使用全局变量

Question

我刚刚开始使用Python，通过LPtHW逐步学习。我正在做练习36，让你设计你自己的游戏。我正在尝试制作一个非常基础的游戏，但在避免全局变量时遇到了麻烦。例如，在与怪物战斗时，它会检查你是否有剑。目前我是这样做的:首先创建全局变量== = 0，然后当你获得剑时，它的值被更改为1，然后当你与怪物战斗时，如果全局剑为1，那么你就赢了。我如何更改我的代码以避免使用全局变量？

Answer 1

使用类是避免使用全局变量的主要方法。

例如，您可以创建一个Player类，其属性表示玩家是否拥有一把剑，而不是在程序开始时为剑声明一个全局变量。

在这个类中，您可以创建一个返回玩家是否有剑的方法，从而避免在类Player之外使用变量。

class Player():
    def __init__(self, sword):
        self.sword = sword
    def playerHasSword():
        return self.sword

Answer 2

这是一个非常简单的类。(包括打架！)

import random
class PlayerKilled(Exception): #player died
     pass #just a mechanism to detect killing a player

DAMAGE_TABLE = { #how much damage for weapons
   "MACE":6,
   "SWORD":8,
   "DAGGER":5,
   "FISTS":3
}
class MOB:
    def __init__(self,name,hp,weapon="FISTS"):
        self.name = name
        self.hp = hp
        self.ac = 3 # defense
        self.level = 1
        self.weapon = weapon
        self.dead = False
    def battle(self,MOB2):
        attacker,defender = self, MOB2
        if random.random() > 0.5:
            print "%s Attacks First!"%MOB2.name
            attacker,defender = defender,attacker
        while not self.dead and not MOB2.dead:
            attacker.attack(defender)
            attacker,defender = defender,attacker
        return defender
    def attack(self,MOB2):
        dmg = sum(random.randint(1,DAMAGE_TABLE[self.weapon]) for _ in range(self.level))
        print "%s Attacks with %s for %s DMG!"%(self.name,self.weapon,dmg)
        try:
           MOB2.defend(dmg)
        except PlayerKilled:
           print "%s has killed %s"%(self.name,MOB2.name)

    def defend(self,dmg):
        if sum(random.randint(0,self.ac) for _ in range(self.level)) > dmg:
            print "%s blocks the attack"%self.name
            return 
        self.hp = self.hp - dmg
        if self.hp < 0:
            print "%s has died!"%self.name
            self.hp = 0
            self.dead = True
            raise PlayerKilled

p1 = MOB("player",20,"DAGGER")
p2 = MOB("vampire",20,"FISTS")
winner = p1.battle(p2)
print "%s WINS with %s HP left!"%(winner.name,winner.hp)