(3) the topic
Save the children.
Thank you

CodePudding user response:

Yourself to the whole data well, and then such as lei feng, lei feng don't like to knock their data code,

Given the thinking of 1, 3 items code

 

Class_1={' a ', 'b', 'c'} 
Class_2={' b ', 'd'} 
Class_3={' a ', 'e', 'f'} 

Class_all=class_1 | class_2 | class_3 

# set collection, the total number of elective courses 
Print (len (class_all)) 


# set collection, choose the number of 3 course 
Class_all=class_1 & amp; Class_2 & amp; Class_3 

Print (len (class_all)) 

CodePudding user response:

7 # line that is set and set
11 # line that is set