Can you please explain the output of this code?

Question

class FirstClass:
n = 4
def__init__(self,n):
n = n//4
a = FirstClass(8)
print(a.n)

Answer is 4

Answer 1

The n variable in the class is defined before the __init__ method and has no self prefix. So it's a class attribute and all objects of the class have access to it. On the other hand in the __init__ the n is defined without self and so it has no effect on n copy of objects.
So we'll have n=4 for all objects.

Answer 2

Hi

Quote: "
1 class FirstClass:
2 n = 4
3 def__init__(self,n):
4 n = n//4
5 a = FirstClass(8)
6 print(a.n)

Answer is 4"

Explanation with numbered lines:
At line 2, you define a class variable n & initialize/assign it the value 4.
Then in constructor, line 3, you define an instance variable (or parameter) n, so another variable n.
What constructor does is, line 4 it sets this last instance variable n to its own value divided by 4.
But it doesn't affect the class variable n which has the value 4.
So at line 5, when you create an instance called a of your class receiving 8 as instance variable / parameter, the class variable a.n is initialized with value 4 and is NOT affected by the code in constructor (line 4). Only the instance variable n is set to 8/4 = 2.
Finally, line 6 when you print the class variable a.n value, you get 4 which is fairly logical.

Here is your code updated with renamed class variable & self at line 4 to properly affect your class variable:
1 class FirstClass:
2 myN = 4
3 def__init__(self,n):
4 self.myN = n//4
5 a = FirstClass(8)
6 print(a.myN)

Answer is now 2 as our class variable was updated.

I hope it helps. All the best for your Python classes learning.

P.S.:
You should be able to find more detailed info on class & instance variables in Python tutorial here on SoloLearn.
Otherwise, I found this tutorial on digitalocean that explains & shows clear examples of both kinds of variables:
https://www.digitalocean.com/community/tutorials/understanding-class-and-instance-variables-in-python-3#class-variables

Answer 3

Tom BWDEV it will be more useful to see more answers.

Answer 4

Qasem, sorry didn't see your answer as I was typing mine. You're right too.

Answer 5

Qasem, hopefully & there is the short answer & the long answer, depending on what the users want lol.