List as an argument in class?

Question

How do we pass a list as an argument of a python class?

class My_Class:
    def __init__(self, att, mylist[]):
        self.att=att
        self.mylist = mylist[]

https://stackoverflow.com/questions/36901/what-does-double-star-asterisk-and-star-asterisk-do-for-parameters — Attila Bognár, Nov 26 '18 at 13:35
You can leave off the square brackets `[]` in both your parameter list and the assignment statement. As long as the *type* of `mylist` is a list, it will be treated as a list. — DatHydroGuy, Nov 26 '18 at 13:36
On the off-chance that you are asking about type hinting, it would be `def __init__(self, att, mylist: List[Any])` (assuming you have imported the names `List` and `Any` from the `typing` module). — chepner, Nov 26 '18 at 13:49
Side note: Please don't name your classes like `My_Class`. That looks like [Wordpress class naming conventions](https://make.wordpress.org/core/handbook/best-practices/coding-standards/php/#naming-conventions) which are, IMO, some of the objectively worst conventions on the planet. But we can avoid the "IMO" part here since Python has an [official style guide](https://www.python.org/dev/peps/pep-0008/)! Following PEP 8, you might name your class `MyClass`. — ChrisGPT was on strike, Nov 26 '18 at 13:50

score 2 · Answer 1 · answered Nov 26 '18 at 13:35

2

There's nothing to it, really. In Python we do not need to declare the type of parameters:

class My_Class:
    def __init__(self, att, mylist):
        self.att = att
        self.mylist = mylist

answered Nov 26 '18 at 13:35

Óscar López

The how do I print the list? print(instance.mylist)? – Azazel Nov 26 '18 at 13:41
5

@Azazel, why would you think you should use `instance`? It looks like you would benefit from a Python tutorial. Start with the basics, which will cover things like variable names and types (so you won't make mistakes like `mylist[]`), then look for one that deals with object-oriented Python code. – ChrisGPT was on strike Nov 26 '18 at 13:42
by instance I meant instance of that My_Class.....something like: class1=My_Class('ABC', ['123','456','789']) – Azazel Nov 26 '18 at 13:47

score 2 · Accepted Answer · edited Nov 26 '18 at 13:46

2

You don't need to specify that it is a list. Python is a dynamically and strongly typed language.

class My_Class:
    def __init__(self, att, mylist):
        self.att = att
        self.mylist = mylist

edited Nov 26 '18 at 13:46

chepner

answered Nov 26 '18 at 13:36

edilio

score 0 · Answer 3 · answered Nov 26 '18 at 13:35

0

You simply pass a reference to the list

class My_Class:
def __init__( self, att, mylist ):
    self.att=att
    self.mylist = mylist

answered Nov 26 '18 at 13:35

rachid el kedmiri

3 Answers3