[英]AttributeError: '_pygit2.Reference' object has no attribute 'get_object'
[英]How to get a reference to an object attribute?
我正在寻找一种方法,以根据解析为方法的值来更改对象属性。 例如:
class Character(object):
def __init__(self, hp, mp, st, ag):
self.hp = hp
self.mp = mp
self.st = st
self.ag = ag
def increase_stat(self, stat, value):
''' Increase one of the attributes
(hp, mp, st, ag) by a given value.
'''
stat_dict = {'hp': self.hp,
'mp': self.mp,
'st': self.st,
'ag': self.ag}
stat_attr = stat_dict.get(stat)
# below should be equivalent to self.hp += value
stat_attr += value
hero = Character(hp=10, mp=4, st=3, ag=2)
hero.increase_stat(stat='hp', value=2)
# this should increase the hp by 2
print(hero.hp == 12)
我知道这不起作用,因为stat_dict.get(stat)返回self.hp指向的值,而不是实际的self.hp对象。
我没有将属性作为dict的值,而是使用增加每个单独stat的方法。
class Character(object):
def __init__(self, hp, mp, st, ag):
self.hp = hp
self.mp = mp
self.st = st
self.ag = ag
def increase_stat(self, stat, value):
''' Increase one of the attributes
(hp, mp, st, ag) by a given value.
'''
stat_method_dict = {'hp': self._increase_hp,
'mp': self._increase_mp,
'st': self._increase_st,
'ag': self._increase_ag}
alter_stat_method = stat_method_dict.get(stat)
alter_stat_method(value)
def _increase_hp(self, value):
self.hp += value
def _increase_mp(self, value):
self.mp += value
def _increase_st(self, value):
self.st += value
def _increase_ag(self, value):
self.ag = value
hero = Character(hp=10, mp=4, st=3, ag=2)
hero.increase_stat(stat='hp', value=2)
# this should increase the hp by 2
print(hero.hp == 12)
我的问题是它是重复的,如果我决定向该类添加更多属性/统计信息,那么这只会增加重复方法的数量。 我想知道是否有比我上面制作的更好的解决方案?
现在看来非常明显。 谢谢大家
class Character(object):
def __init__(self, hp, mp, st, ag):
self.hp = hp
self.mp = mp
self.st = st
self.ag = ag
def increase_stat(self, stat, value):
''' Increase one of the attributes
(hp, mp, st, ag) by a given value.
'''
current = getattr(self, stat)
setattr(self, stat, current+value)
您的统计资料确实没有任何目的。 使用getattr
和setattr
动态处理属性。 因此,类似:
def increase_stat(self, stat, value):
setattr(self, stat, value + getattr(self, stat))
因此,例如:
In [30]: class Dummy:
...: def __init__(self):
...: self.intelligence = 0
...: self.strength = 10
...: self.hp = 100
...: def increase_stat(self, stat, value):
...: setattr(self, stat, value + getattr(self, stat))
...:
In [31]: d = Dummy()
In [32]: d.strength
Out[32]: 10
In [33]: d.increase_stat('strength', 10)
In [34]: d.strength
Out[34]: 20
也许更容易阅读:
def increase_stat(self, stat, value):
current = getattr(self, stat)
setattr(self, stat, current + value)
请注意,这比直接操作实例__dict__
更好,后者将与property
对象之类的描述符一起破坏。 更不用说没有__dict__
对象,例如带有__slots__
类型
您可以使用__setitem__
方法获得更简洁的解决方案:
class Character(object):
def __init__(self, *args):
self.__dict__ = dict(zip(['hp', 'mp', 'st', 'ag'], args))
def __setitem__(self, name, val):
self.__dict__[name] += val
hero = Character(10, 4, 3, 2)
hero['hp'] = 2
print(hero.hp)
输出:
12
但是,也可以使用自定义方法来实现此策略:
class Character(object):
def __init__(self, *args):
self.__dict__ = dict(zip(['hp', 'mp', 'st', 'ag'], args))
def increase_stat(self, stat, value):
self.__dict__[stat] += value
hero = Character(10, 4, 3, 2)
hero.increase_stat(stat='hp', value=2)
输出:
12
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