How can I do something like this using __getitem__?
class Computers:
def __init__(self, processor, ram, hard_drive):
self.processor = processor
self.ram = ram
self.hard_drive = hard_drive
what I want to be able to do is
C = Computers('2.4 Ghz','4 gb', '500gb')
C['h'] to return 500gb
and C['p','r','h'] to return ('2.4 Ghz','4 gb', '500gb')
Yes, you can. In both cases, your __getitem__ method would be called with one object. In the first case, you are passed a single string object, in the second, you passed a tuple containing 3 strings.
Handle both cases:
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)
Demo, including error handling:
>>> 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'
