4. python- operator (alternative syntax)

Identity operator

 1 x = 258
 2 y = 258
 3 print(id(x),id(y))
 4 print(id(x)==id(y))
 5 
 6 2956579849680 2956579849136
 7 False
 8 
 9 print(x is y)
10 
11 False

Chain assignment

1 x = y = z = 10
 2  print (x, y, z)
 3  
4 10 10 10

Cross assignment

1 x = 10
 2 = 20
 3 x, y = y, x
 4  print (x, y)
 5  
6 20 October

unzip

Fast and can get more than a one-time list of values

 1 duan_hobby_list = ['read','run']
 2 hobby1 = duan_hobby_list[0]
 3 hobby2 = duan_hobby_list[1]
 4 print(hobby1,hobby2)
 5 
 6 read run
 7 
 8 hobby1,hobby2 = duan_hobby_list
 9 print(hobby1,hobby2)
10 
11 read run
12 
13 duan_hobby_list1 = ['read','run','sing', ' Football ' , ' Basketball ' ]
 14 hobby1, hobby2, _, _, _ = duan_hobby_list1
 15  Print (hobby1, hobby2)
 16  
. 17  Read RUN
 18 is  
. 19 hobby1, hobby2, * _ = duan_hobby_list1   # all following "*" represents that the corresponding assignment position 
20 is  Print (hobby1, hobby2)
 21 is  
22 is  Read RUN
 23 is  
24 hobby1, * _, hobby5 = duan_hobby_list1
 25  Print (hobby1, hobby5)
 26 is  
27 Read Basketball