python 常用知识点

>>> dic = {‘k1‘:‘v1‘,‘k2‘:‘v2‘,‘k3‘:‘v3‘}
>>> dic.get(‘k4‘)
>>> p = dic.get(‘k4‘)
>>> print p
None

>>> dic.get(‘k4‘,‘v4‘)
‘v4‘
>>> dic.get(‘k3‘,‘v4‘)
‘v3‘
>>> dic.get(‘k2‘,‘v4‘)
‘v2‘
>>> dic.get(‘k1‘,‘v4‘)
‘v1‘

>>> dic.keys()
[‘k3‘, ‘k2‘, ‘k1‘]
>>> dic.values()
[‘v3‘, ‘v2‘, ‘v1‘]
>>> for k,v in dic.items():
... print k,v
... 
k3 v3
k2 v2
k1 v1
>>> for k,v in dic.items():
... print k,v,
... 
k3 v3 k2 v2 k1 v1
>>>