Python - 在条件下创建继承的类属性

Question

class WineComponents(object):
def __init__(self, aroma, body, acidity, flavor, color):
self.aroma = aroma
self.body = body
self.acidity = acidity
self.flavor = flavor
self.color = color

可以像这样实例化：

wine = Color(aroma='80%', body='30%', acidity='35%', flavor='90%', color='Red')

那么我希望能够创建将继承WineComponents()的特定类：

class Color(WineComponents): 
def receipe(self):
pass

并且在某些条件下还要有自己的属性，如下所示：

class Color(WineComponents):
if self.color == 'Red':
region  = 'France'
type = 'Bordeaux'
def receipe(self):
pass

调用属性：

print wine.region

但这不起作用：

if self.color == 'Red':
NameError: name 'self' is not defined

有解决方法吗？

Answer 1

这是我的五便士：

class WineComponents(object):
def __init__(self, aroma, body, acidity, flavor, color):
self.aroma = aroma
self.body = body
self.acidity = acidity
self.flavor = flavor
self.color = color

class Color(WineComponents):
def __init__(self, aroma, body, acidity, flavor, color):
super(Color, self).__init__(aroma, body, acidity, flavor, color)
if self.color == 'Red':
self.region = 'France'
self.type = 'Bordeaux'
def receipe(self):
pass
if __name__ == '__main__':
wine = Color(aroma='80%', body='30%', acidity='35%', flavor='90%', 
color='Red')
print (wine.region, wine.type)

Answer 2

您可以使用属性执行此操作

class Wine(object):
def __init__(self, aroma, body, acidity, flavor, color):
self.aroma = aroma
self.body = body
self.acidity = acidity
self.flavor = flavor
self.color = color
@property
def region(self):
if self.color == 'Red':
return 'France'
else:
raise NotImplementedError('unknown region for this wine')

可以这样称呼：

>>> wine = Wine(aroma='80%', body='30%', acidity='35%', flavor='90%', color='Red')
>>> wine.region
'France'