List additions and deletions in Python and other related methods

1. There are three ways to add

1 #"", "" Three Ways2 3 #Append ()4Li = ['python','Java','C + +']5Li.append (['these are all programming languages .'])6 Print(LI)#output results: [' python ', ' Java ', ' C + + ', [' These are programming languages ']]7            #also note that append () is not a return value, such as: Print (Li.append ()), and the return result is None8 9 #Insert () is added by index, in the previous bit of the indexTenLi = ['python','Java','C + +'] OneLi.insert (2,'I love Python .') A Print(LI)#output Result: [' python ', ' Java ', ' I love python ', ' C + + '] -  - #extend () iteration to add theLi = ['python','Java','C + +'] -Li.extend ('AAAAA') - Print(LI)#output results: [' python ', ' Java ', ' C + + ', ' a ', ' a ', ' a ', ' a ', ' a ']

2. Deletion of four methods

1 # "" ""2 3 #pop ()4Li = ['python','Java','C + +']5Li.pop (1)6 Print(LI)#output Result: [' Python ', ' C + + '], if Li.pop (), the last element is deleted by default7 8 #Remove ()9Li = ['python','Java','C + +']TenLi.remove ('Java') One Print(LI)#output Result: [' Python ', ' C + + '] A  - #del: Delete According to the location of the slice -  theLi = ['python','Java','C + +'] - delLi[1:2] - Print(LI)#output Result: [' Python ', ' C + + '] -  + #Clear (): Empty list -  +Li = ['python','Java','C + +'] A li.clear () at Print(LI)#output Result: []

3. Change according to index or slice

1 #Change : According to the index or slice to change2 3Li = ['python','Java','C + +']4LI[2] ='C'5 Print(LI)#output Result: [' python ', ' Java ', ' C ']6Li = ['python','Java','C + +']7Li[0:1] ='I must insist on learning Python'8 Print(LI)#output: [' I ', ' one ', ' Set ', ' firm ', ' Hold ', ' learn ', ' XI ', ' P ', ' y ', ' t ', ' h ', ' o ', ' n ', ' Java ', ' C + + ']

4. Check the cycle or slice to check 5. Public Method 5.1 Len () method

1 # Len () 2 li = ['python''java''C + + ' ]3print(len (LI))

5.2 Count () method

1 # Coount () 2 li = ['python''java''C + + ' ]3print(Li.count ('python'))

5.3 Index () method

1 # index () 2 li = ['python''java''C + + ' ]3print(Li.index ('python'))

6. Sorting

1 #forward Sort2Li = [1,3,6,4,8,2, 0]3 Li.sort ()4 Print(LI)#output results: [0, 1, 2, 3, 4, 6, 8]5 #Reverse Sort6Li = [1,3,6,4,8,2, 0]7Li.sort (reverse=True)8 Print(LI)#Output results: [8, 6, 4, 3, 2, 1, 0]9 #Reverse SortTenLi = [1,3,6,4,8,2, 0] One Li.reverse () A Print(LI)#output results: [0, 2, 8, 4, 6, 3, 1]

7. The operation iterates over the join method of the object, as well as the method of converting the list to a string, some of which can also be used instead of the for method to traverse

1 li = ['fd','dfs','fr' ,'Q2']2'*'. Join ( Li)3print(s)

List additions and deletions in Python and other related methods