>>> dic['name']='zhangsan'
>>> dic

{'name': 'zhangsan'}

>>> key='age'
>>> value=30
>>> dic[key]=value
>>> dic

{'age': 30, 'name': 'zhangsan'}

>>> dic.setdefault('sex','male')
'male'
>>> key='id'
>>> value='001'
>>> dic.setdefault(key,value)
'001'
>>> dic
{'id': '001', 'age': 30, 'name': 'zhangsan', 'sex': 'male'}

>>> for key in dic:
...   print 'key is %s,value is %s'%(key,dic[key])
...
key is id,value is 001
key is age,value is 30
key is name,value is zhangsan
key is sex,value is male

>>> for key,value in dic.items():
...   print 'key is %s,value is %s'%(key,value)
...
key is id,value is 001
key is age,value is 30
key is name,value is zhangsan
key is sex,value is male