class JobDb(object):
def __init__(self):
self.data = []
self.all = set()
self.free = []
self.index1 = {}
self.index2 = {}
self.index3 = {}
def _indices(self,(key1,key2,key3)):
indices = self.all.copy()
wild = False
for index,key in ((self.index1,key1),(self.index2,key2),
(self.index3,key3)):
if key is not None:
indices &= index.setdefault(key,set())
else:
wild = True
return indices, wild
def __getitem__(self,key):
indices, wild = self._indices(key)
if wild:
return dict(self.data[i] for i in indices)
else:
values = [self.data[i][-1] for i in indices]
if values:
return values[0]
def __setitem__(self,key,value):
indices, wild = self._indices(key)
if indices:
for i in indices:
self.data[i] = key,value
elif wild:
raise KeyError(k)
else:
if self.free:
index = self.free.pop(0)
self.data[index] = key,value
else:
index = len(self.data)
self.data.append((key,value))
self.all.add(index)
self.index1.setdefault(key[0],set()).add(index)
self.index2.setdefault(key[1],set()).add(index)
self.index3.setdefault(key[2],set()).add(index)
def __delitem__(self,key):
indices,wild = self._indices(key)
if not indices:
raise KeyError
self.index1[key[0]] -= indices
self.index2[key[1]] -= indices
self.index3[key[2]] -= indices
self.all -= indices
for i in indices:
self.data[i] = None
self.free.extend(indices)
def __len__(self):
return len(self.all)
def __iter__(self):
for key,value in self.data:
yield key
例子:
>>> db = JobDb()
>>> db['new jersey', 'mercer county', 'plumbers'] = 3
>>> db['new jersey', 'mercer county', 'programmers'] = 81
>>> db['new jersey', 'middlesex county', 'programmers'] = 81
>>> db['new jersey', 'middlesex county', 'salesmen'] = 62
>>> db['new york', 'queens county', 'plumbers'] = 9
>>> db['new york', 'queens county', 'salesmen'] = 36
>>> db['new york', None, None]
{('new york', 'queens county', 'plumbers'): 9,
('new york', 'queens county', 'salesmen'): 36}
>>> db[None, None, 'plumbers']
{('new jersey', 'mercer county', 'plumbers'): 3,
('new york', 'queens county', 'plumbers'): 9}
>>> db['new jersey', 'mercer county', None]
{('new jersey', 'mercer county', 'plumbers'): 3,
('new jersey', 'mercer county', 'programmers'): 81}
>>> db['new jersey', 'middlesex county', 'programmers']
81
>>>
编辑:现在使用通配符(None)查询时返回字典，否则返回单值。
