Some common methods and functions of the Python list

Learn some new knowledge about the Python list, self-organized, convenient for everyone to refer to:

# !/usr/bin/env python # _*_ coding:utf-8 _*_ # File_type: List of common methods of operation, and some commonly used functions # Filename:list_function_test.py # Author:smelond

Method:

1, List.count () Statistics:

List = [6, 4, 5, 2, 744, 1, 76, 13, 8, 4]
List_count = List.count (4)  #  count the number of occurrences of an element in the list print("4 has occurred in the list%s times " % List_count)

4 appears in the list 2 times

2, List.append () Add object:

List = [6, 4, 5, 2, 744, 1, 76, 13, 8, 4]
List.append ("obj")  #  Add a new object to the end of the list print(list)

[6, 4, 5, 2, 744, 1,, 8, 4, ' obj ']

3. List.extend () extension list:

List = [6, 4, 5, 2, 744, 1, 76, 13, 8, 4]
List1 = [123, 456, 789]list.extend (list1)  #  extension list, Append multiple values from another list at the end of the list (equivalent to copying List1 elements to list)print(list)

[6, 4, 5, 2, 744, 1, 76, 13, 8, 4, 123, 456, 789]

4. List.pop () Delete object:

List = [6, 4, 5, 2, 744, 1, 76, 13, 8, 4]
List.pop (1)# move out of an element in the list (the last element by default)print(list)

[6, 5, 2, 744, 1, 76, 13, 8, 4]

5, List.remove () delete the match:

List = [6, 4, 5, 2, 744, 1, 76, 13, 8, 4]
List.remove (4)  #  Removes the first occurrence of a value in a list (moves only the first one)print(list)

[6, 5, 2, 744, 1, 76, 13, 8, 4

6. List.insert () Insert object:

List = [6, 4, 5, 2, 744, 1, 76, 13, 8, 4]
" Test ") # inserts an object into the third position of the list Print (list) ['test', 2, 744, 1, 76, 13, 8, 4]

7. List.copy Copy list:

List = [6, 4, 5, 2, 744, 1,, 8, 4 = list.copy ()    #  Copy a copy, the original value and the newly copied variable do not affect the print c5> (List1) [4, 8, 13, 76, 1, 744, 2, 5, 4, 6]

8, List.reverse () reverse order:

List = [6, 4, 5, 2, 744, 1, 76, 13, 8, 4]
List.reverse ()  #  Reverse list of elements in print(list) [4, 8, 13, 76, 1, 744, 2, 5, 4, 6]

9, List.index () get the index:

 # Modify the first get to object 
   list = [6, 4, 5, 2, 744, 1, 8, 4] 
 List_index = List.index (4) #   Find the index position of the first occurrence of a value from the list  List[list_index] = 999 #   Change the index we get to 999  print  (list) 
 
 [6, 999, 5, 2, 744, 1,,, 8, 4] 

# Modify all get to Object
List = [6, 4, 5, 2, 744, 1, 76, 13, 8, 4]
 for in range (List.count (4)):  #  using the list method, count finds how many elements are equal to 4, and then the For loop    List_index = List.index (4)  #  every 4 found is used to assign to List_index    list[list_index] = 999  # Finally, we will change the index we obtained to 999    Print　　　(list) # print I put in for loop inside, so output two, but from here we can see, first changed the first 4, the second time changed the second 4

[6, 999, 5, 2, 744, 1, 76, 13, 8, 4]
[6, 999, 5, 2, 744, 1, 76, 13, 8, 999]

10, List.sort () Sort:

List = [6, 4, 5, 2, 744, 1, 76, 13, 8, 4]
List.sort ()# sorts the original list. Sort by ASCII print(list)

[1, 2, 4, 4, 5, 6, 8, 13, 76, 744]

11, List[obj] Step:

List = [6, 4, 5, 2, 744, 1,, 8, 4]print(List[0:-1:2])  #  This is called the step, and the last 2 represents every 2 elements printing a Times, the default is one step print(list[::2])  #  This effect is similar to above, if it is starting from 0, you can put 0 omitted not to write

Function:

12, Len (list):

List = [6, 4, 5, 2, 744, 1,, 8, 4]len    (list)#  Returns the number of list elements print(len (list)) 10

13. Max (list):

List = [6, 4, 5, 2, 744, 1,, 8, 4]len    (list)#  returns the maximum value of the list element print(Len (li ST))744

14, Min (list):

List = [6, 4, 5, 2, 744, 1,, 8, 4]len    (list)#  Returns the minimum value of the list element print  (Len (list)) 744

Last update time: 2017-11-18-19:26:35

Some common methods and functions of the Python list