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Adding and traversing methods of python dictionary key-value pairsAdd key-value pairs
First define an empty dictionary
>>> dic={}
Directly Assign a value to a key that does not exist in the dictionary to add
>>> dic['name']='zhangsan'
>>> dic
{'name': 'zhangsan'}
This method can also be used if the key or value are both variables
>>> key='age'
>>> value=30
>>> dic[key]=value
>>> dic
{'age': 30, 'name': 'zhangsan'}
Here you can see that the data in the dictionary is not arranged in order. If you are interested, you can search for the hash table in the data structure
You can also use the setdefault method of the dictionary
##
>>> dic.setdefault('sex','male')
'male'
>>> key='id'
>>> value='001'
>>> dic.setdefault(key,value)
'001'
>>> dic
{'id': '001', 'age': 30, 'name': 'zhangsan', 'sex': 'male'}
Traverse the dictionary
There are two methods here
Method 1: Get the key first, and then pass dic[key ]Get value
>>> 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
Method 2: Unpack the tuple list returned by the dictionary items() method in sequence
>>> 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 maleIf you are not familiar with list, tuple and sequence unpacking, it is best to Baidu to understand them in depth. You can understand it by combining the arrays, List classes and hash tables you are familiar with in C# or JAVA languageThe above method of adding and traversing python dictionary key-value pairs is all the content shared by the editor. , I hope it can give everyone a reference, and I also hope everyone will support the PHP Chinese website. For more articles related to adding and traversing python dictionary key-value pairs, please pay attention to the PHP Chinese website!
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