• get(key[, default])?

Return the value for key if key is in the dictionary, else default. If default is not given, it defaults to None
, so that this method never raises a [KeyError].
----------------------------------------------
exception KeyError:
Raised when a mapping (dictionary) key is not found in the set of existing keys.

舉個(gè)栗子：

>>> def get_rank(points):
...   rank_str =  {1:'A', 11:'J', 12:'Q', 13:'K'}.get(points, str(points))
...   return rank_str
... 
>>> get_rank(12)
'Q'
>>> get_rank(3)
'3'

• Dictionary view objects?

The objects returned by dict.keys(), dict.values() and dict.items()
are view objects.

>>> fruit = {1:'apple', 2:'banana', 3:'orange'}
>>> fruit
{1: 'apple', 2: 'banana', 3: 'orange'}

>>> fruit.keys()
dict_keys([1, 2, 3])
>>> fruit.values()
dict_values(['apple', 'banana', 'orange'])
>>> fruit.items()
dict_items([(1, 'apple'), (2, 'banana'), (3, 'orange')])