要实现subscriptable对象很容易,只需在此对象的类定义中实现__getitem__
即可。
但是现在我想实现一个可订阅的类。例如,我想实现以下代码:
class Fruit(object):
Apple = 0
Pear = 1
Banana = 2
#________________________________
#/ Some other definitions, \
#\ make class 'Fruit' subscriptable. /
# --------------------------------
# \ ^__^
# \ (oo)\_______
# (__)\ )\/\
# ||----w |
# || ||
print Fruit['Apple'], Fruit['Banana']
#Output: 0 2
我知道getattr
可以做同样的事情,但我觉得下标访问更优雅。
发布于 2012-07-13 19:01:41
似乎是通过改变元类来工作的。对于Python 2:
class GetAttr(type):
def __getitem__(cls, x):
return getattr(cls, x)
class Fruit(object):
__metaclass__ = GetAttr
Apple = 0
Pear = 1
Banana = 2
print Fruit['Apple'], Fruit['Banana']
# output: 0 2
在Python3中,您应该直接使用Enum:
import enum
class Fruit(enum.Enum):
Apple = 0
Pear = 1
Banana = 2
print(Fruit['Apple'], Fruit['Banana'])
# Output: Fruit.Apple, Fruit.Banana
print(Fruit['Apple'].value, Fruit['Banana'].value)
# Output: 0 2
发布于 2016-03-15 02:18:31
在你的类中添加类似这样的内容:
class Fruit(object):
def __init__(self):
self.Fruits = {"Apple": 0, "Pear": 1, "Banana": 2}
def __getitem__(self, item):
return self.Fruits[item]
发布于 2020-03-23 03:52:27
在@LuisKleinwort's answer上展开,如果您想对所有类属性执行此操作:
fruits_dict = {'apple':0, 'banana':1}
class Fruits(object):
def __init__(self, args):
for k in args:
setattr(self, k, args[k])
def __getitem__(self, item):
return getattr(self, item)
fruits = Fruits(fruits_dict)
print(fruits.apple)
print(fruits['apple'])
https://stackoverflow.com/questions/11469025
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