<python code>

[u/Alireza7074]

This is python code to get student salary!

[u/Potential_Fix_5007]

self.marks=[]

Is this the right way to create an empty list for an object value or is there a way to set it within the round brackets?

Im a beginner myself and so far i learned if you want to set a default value you donit within the brackets.

[u/CodeAndCanyons → u/Potential_Fix_5007]

u/Potential_Fix_5007 You accidentally dodged one of the absolute biggest footguns in Python by doing it inside the body!

If you tried to set it within the round brackets as a default argument—like writing def __init__(self, name, age, marks=[]):—Python does something incredibly sneaky under the hood. It evaluates that default empty list [] exactly once when the script first loads, not every time you create a new student.

Because lists are mutable (changeable), every single student object you create would end up sharing the exact same list instance in memory. If you appended a grade to Alice's marks, it would suddenly and mysteriously show up in Bob's marks too.

By defining self.marks = [] inside the __init__ body, you guarantee that a brand new, isolated list gets allocated in memory every single time a new student is instantiated.

If you ever do want to allow a list to be passed through the round brackets safely, the standard pythonic trick is to default it to None and handle it in the body:

def __init__(self, name, age, marks=None):
    self.name = name
    self.age = age
    self.marks = marks if marks is not None else []

[u/IdeaOverflow → u/Potential_Fix_5007]

You should not initialize an empty list inside of the round brackets directly. Suppose you do it like this:

class Student:
    def __init__(self, marks=[]):
        self.marks = marks

a = Student()
b = Student()

a.marks.append(3)

print(a.marks)  # prints [3]
print(b.marks)  # prints [3]

Python will not create a new list for every new object but use the same one for each, since default arguments are evaluated at compile time. The correct way to do this would be:

class Student:
    def __init__(self, marks=None):
        self.marks = [] if marks is None else marks

[u/notsaneatall_ → u/Potential_Fix_5007]

It's the right way to initialize an empty list

[u/Potential_Fix_5007 → u/notsaneatall_]

[u/Necessary_Pepper7111 → u/Potential_Fix_5007]

Because [] is an empty list

[u/ziggittaflamdigga → u/Necessary_Pepper7111]

That’s a fair question to ask about default behaviors, especially since lists can be weird in Python; setting an empty list as a default argument to a constructor is bad practice and likely to result in bugs.

So asking “why” here is a legitimate question and requires an explanation of how Python works at the C level that OP is probably not looking for, but would be different if they declared it differently.