在python运算符重载中使用_ugetItem
如何使用在python运算符重载中使用_ugetItem,python,python-3.x,Python,Python 3.x,如何使用\uu getitem\uu执行类似操作 class Computers: def __init__(self, processor, ram, hard_drive): self.processor = processor self.ram = ram self.hard_drive = hard_drive 我想做的是 C = Computers('2.4 Ghz','4 gb', '500gb') C['h']返回50
\uu getitem\uu
执行类似操作
class Computers:
def __init__(self, processor, ram, hard_drive):
self.processor = processor
self.ram = ram
self.hard_drive = hard_drive
我想做的是
C = Computers('2.4 Ghz','4 gb', '500gb')
C['h']
返回500gb
和
C['p','r','h']
返回('2.4 Ghz','4 gb','500gb')是的,您可以。在这两种情况下,您的\uuu getitem\uu
方法都将使用一个对象调用。在第一种情况下,传递一个字符串对象,在第二种情况下,传递一个包含3个字符串的元组
处理两种情况:
def __getitem__(self, item):
attrmap = {'p': 'processor', 'r': 'ram', 'h': 'hard_drive'}
if isinstance(item, str):
return getattr(self, attrmap[item])
# assume a sequence
return tuple(getattr(self, attrmap[i]) for i in item)
演示,包括错误处理:
>>> C = Computers('2.4 Ghz','4 gb', '500gb')
>>> C['h']
'500gb'
>>> C['p', 'r', 'h']
('2.4 Ghz', '4 gb', '500gb')
>>> C['f']
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 9, in __getitem__
KeyError: 'f'
>>> C['p', 'r', 'f']
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 11, in __getitem__
File "<stdin>", line 11, in <genexpr>
KeyError: 'f'
C=计算机('2.4 Ghz'、'4 gb'、'500gb')
>>>C['h']
“500gb”
>>>C['p','r','h']
(‘2.4 Ghz’、‘4 gb’、‘500gb’)
>>>C['f']
回溯(最近一次呼叫最后一次):
文件“”,第1行,在
文件“”,第9行,在\uu getitem中__
键错误:“f”
>>>C['p','r','f']
回溯(最近一次呼叫最后一次):
文件“”,第1行,在
文件“”,第11行,在\uu getitem中__
文件“”,第11行,在
键错误:“f”