Python learns the second day of lists, dictionaries and nesting

Source: Internet
Author: User
Tags shallow copy

1 #!/user/bin/env python2 #-*-coding:utf-8-*-3 __author__='Howie'4names = ['Zhangsan','LiSi','Wangwu',['Lili','dddd'],'Zhaoliu','DAda']5 #A = names[-2:] #如果想取倒数几个数需要吧最后一个省略6A = Names[:3]#If you want to take the first start to the number of numbers you can omit the index value7 Print(A)8Names.append ('Lili')#Append9 Print(names)TenName2 =names.copy () One Print('after a shallow copy:', name2) ANAMES[2] ='Harry' -Names[3][0] ='LILI' - Print('Original list:', names) the Print('the sub-list of the original list is modified after a shallow copy: the', name2) -  - #to import a module if you want to copy it completely - ImportCopy +Name2 =copy.copy (names) - Print('Original list:', names) + Print('after a full copy:', name2) A  at  -  - #Names.pop (1) #删除第二个 - #del names[1] #和上面的差不多一样的 -Names.remove ('LiSi')#Match Delete - Print('Delete', names) inNames.insert (1,'DAda')#Intermediate Insert Value Ask index value - Print(names) toNAMES[2] ='Xiugai' #change is to wait for a second assignment + Print(names) - Print('Query value at index location:', Names.index ('DAda')) the Print('statistics Number of names:', Names.count ('DAda')) * Names.reverse () $Names2 = [' the','3','6','8','1','5']Panax Notoginseng names.extend (names2) - Print('Expansion:', names) the  + #Names.sort () A #print (' sort: ', names) the  +  -  $  $ names.clear () - Print(names)
useful ways to list
1 #!/user/bin/env python2 #-*-coding:utf-8-*-3 __author__='Howie'4list_1 = [1,5,8,6,2,4,3,2,5,1,1,6]5List_2 = Set ([1,5,5,1,1,6,44,11,22])6List_1 =Set (list_1)7 Print(list_1,list_2)8 Print('The intersection can also be done with &:', List_1.intersection (list_2))9 Print('The intersection can also be done with &:', List_1 &list_2)Ten Print('and set:', List_1.union (list_2)) One Print('The set can also be used | To do:', list_1|list_2) A Print('difference set:', List_1.difference (list_2))#1 have but 2 not. - Print('The difference can also be used-to do:', list_1-list_2)#1 have but 2 not. - Print('symmetric difference set:', List_1.symmetric_difference (list_2))#a collection other than intersection the Print('symmetric difference Sets can also be done with ^:', list_1^list_2)#a collection other than intersection -  -List_3 =list_1.union (list_2) - Print('subset:', List_1.issubset (list_2), List_1.issubset (List_3))#Judging is not a subset + Print('Parent Set:', List_3.issuperset (list_1)) -List_4 = Set ([333,5555,66666]) + Print('judge whether there is no intersection if it is not true:', List_1.isdisjoint (list_4)) AList_4.add (44444) atList_4.update ([11111,2222,66,333]) -List_4.remove (333) - Print(List_4)
practical ways to set up
1 #!/user/bin/env python2 #-*-coding:utf-8-*-3 __author__='Howie'4info = {5     'Zhangsan': 500,6     'Lisi': 600,7     'Zhaowu': 7008 }9b = {Ten     'Lisi': 789, One1:2, A3:4 - } - " " the Print (type (info)) - Print (info) - print (info[' Lisi ') - info[' lisi '] = ' John Doe ' + Print (info) - info[' Wangwu '] = ' Harry ' + Print (info) A del info[' Zhaowu '] at Print (info) - Print (Info.get (' Lili ')) - print (' Lili ' in info) -  - info.setdefault (' Lisi ', {456}) - Print (info) in  - Info.update (b) to " " +A =Info.items () -A = Info.fromkeys ([7,8,9]) the  * PrintA
the practical way of dictionaries

Python learns the second day of lists, dictionaries and nesting

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