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