将字符串转换为对象Python [英] Converting String into Object Python

问题描述

我刚刚开始学习Python几个星期前，我开始写一个基于文本的冒险游戏。我有一些麻烦找到一个好的方法来将字符串转换为类的实例，而不是使用eval（），我读过的是不安全的。下面是我的工作：

I've just started learning Python a couple of weeks ago, and I started writing a text-based adventure game. I'm having some trouble finding a good way to convert strings into instances of a class, other than using eval(), which I've read isn't safe. For reference, here's what I'm working with:

class Room(object):
    """Defines a class for rooms in the game."""
    def __init__(self, name, unlocked, items, description, seen):
        self.name = name
        self.unlocked = unlocked
        self.items = items
        self.description = description
        self.seen = seen


class Item(object):
    """ Defines a class of items in rooms."""
    def __init__(self, name, actions, description):
        self.name = name
        self.actions = actions
        self.description = description



def examine(input):
    if isinstance(eval(input), Room):
        print eval(input).description
    elif isinstance(eval(input), Item):
        print eval(input).description
    else:   
        print "I don't understand that."

如果输入是字符串，那么如何安全地将其作为类对象并访问data属性。描述？

If input is a string, how do I safely make it a class object and access the data attribute .description? Also, if I'm going about this in entirely the wrong way, please feel free to suggest an alternative!

推荐答案

使用一个字典：

lookup = {'Room': Room(), 'Item': Item()}
myinstance = lookup.get(input)
if myinstance is not None:
    print myinstance.description

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