Python 面向对象编程（OOP）问题

Question

class User:
 def __init__(self,user_id, username):
    self.id=user_id
    self.username=username
    self.followers=0
    self.following=0
 def follow(self,user):
   user.followers +=1
   self.following +=1

user_1=User("001","jack")
user_2=User("002","luck")

user_1.follow(user_2)    
print(user_1.followers)
print(user_1.following)

why is the answer 0 and 1 when I print (user_1.followers) and print(user_2.following). I can't tell from where is pulling the value, is it from the constructor or method. Thanks

Answer 1

In your example above, user_1 follows user_2. Therefore, user_1 has NO followers (yet) but IS following user_2. Hence the output:

print(user_1.followers) # 0
print(user_1.following) # 1

Hope this helps...