整理Python最基本的操作字典的方法

>>> info = {}
>>> info = dict()

>>> info = {"name" : 'cold'}
>>> info = dict(name = 'cold')    # 更优雅

>>> key = 'name'
>>> info = { key :'cold'} # {'name':'cold'}
>>> info = dict(key = 'cold') # {'key': 'cold'}

>>> info = {}.fromkeys(['name', 'blog'])
>>> info
{'blog': None, 'name': None}
>>> info = dict().fromkeys(['name', 'blog'])
>>> info
{'blog': None, 'name': None}
>>> info = dict().fromkeys(['name', 'blog'], 'linuxzen.com')
>>> info
{'blog': 'linuxzen.com', 'name': 'linuxzen.com'}

>>> info = {'name':'cold', 'blog':'linuxzen.com'}
>>> info['name']
'cold'

>>> info = dict(name= 'cold', blog='www.linuxzen.com')
>>> info.get('name')
'cold'
>>> info.get('blogname')
None
>>> info.get('blogname', 'linuxzen')
'linuxzen'

>>> info = dict()
>>> info['name'] = 'cold'
>>> info['blog'] = 'linuxzen.com'
>>> info
{'blog': 'linuxzen.com', 'name': 'cold'}
>>> info
{'blog': 'linuxzen.com', 'name': 'cold night'}

>>> info = dict(name='cold', blog='linuxzen.com')
>>> info.update({'name':'cold night', 'blogname':'linuxzen'})
>>> info
{'blog': 'linuxzen.com', 'name': 'cold night', 'blogname': 'linuxzen'}
>>> info.update(name='cold', blog='www.linuxzen.com') # 更优雅
>>> info
{'blog': 'www.linuxzen.com', 'name': 'cold', 'blogname': 'linuxzen'}

>>> info = dict(name='cold', blog='linuxzen.com')
>>> info
{'blog': 'linuxzen.com', 'name': 'cold'}
>>> del info['name']
>>> info
{'blog': 'linuxzen.com'}

>>> info = dict(name='cold', blog='linuxzen.com')
>>> info.pop('name')
'cold'
>>> info
{'blog': 'linuxzen.com'}

>>> info = dict(name='cold', blog='linuxzen.com')
>>> info.keys()
['blog', 'name']

>>> info = dict(name='cold', blog='linuxzen.com')
>>> for key, value in info.items():
...   print key, ':', value
... 
blog : linuxzen.com
name : cold