Additions and deletions of dictionaries in 2018.8.1 Python and other operations

A simple introduction to the dictionary

1. Dict with {} to indicate key value pair data {Key:value} uniqueness

2, the key must be a hash, immutable data type can be used as a key in the dictionary

There is no limit to the value

3. Known hash (immutable) data type: Int,str,tuple,bool

Non-hashed (variable) data type: List,dict,set

4. Syntax: {key1:value1,key2:value2}

DIC = {'name':'Alex',' Age': 9000}#string Printdic (DIC)= {1:'a', 2:'b', 3:'C'}#Digital Printdic (DIC)= {True:'1', False:'0'}#Boolean value Printdic (DIC)= {():'ABC'}#Meta-group Printdic (DIC)= {[+]:'ABC'} Print(DIC)

Second, the dictionary additions and deletions and other related operations

1, increase

Dic[key] = value

Dic.setdefault (Key,value) If the key exists in the dictionary without any action, add

Can be queried by key, without this key to return none

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2. By deleting

Dic.pop (Key) has a return value that is returned by the deleted value
Dic.del Dic[key]
Dic.popitem () Random deletion
Dic.clear () Empty dictionary

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3, change

Dic[key] = value
Dic.update (dictionary)

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4. Check

Dic.get (Key)
Dic[key]
For loop
SetDefault (Key)

DIC = {'Yi Master':'Sword Saint','Jian Hao':'Nursery','Bush LUN':'Big Sword'} forIinchDIC:Print(i)#The for loop defaults to getting the keys in the dictionaryPrint(dic['Yi Master Father'])                   #View 1 The query will error when there is no such key.Print(Dic.get ('Yi Master','You're stupid, no!'))    #See 2 No return none can specify what to returnPrint(Dic.setdefault ('Yi Tai Normal Lake'))        #View 3 no return none

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5. Other related operation

Print(Dic.keys ())#(High copy list)Print(Dic.values ())#(High copy list)Print(Dic.items ())#(High imitation list, tuple in list) forIinchDic.keys ():Print(i)#get to each key in the dictionary forIinchDIC:Print(i)#get to each key in the dictionary forIinchdic.values ():Print(i)#get to every value in a dictionary forKey,valueinchDic.items ():Print(Key,value)#Deconstruction

6, the Dictionary of Nesting

DIC = {    'name':'Wang Feng',    ' Age': 43,    'wife':{        'name':'International Chapter',        ' Age': 39,        'Salary': 100000    },    'Baby':[        {'name':'Big Bear',' Age': 18},        {'name':'Kumaji',' Age': 15},]}dic['Baby'][0][' Age'] = 19Print(DIC)

Additions and deletions of dictionaries in 2018.8.1 Python and other operations