Python 3: Invalid Syntax Error when using * operator in __init__ between pre-defined values defined in-scope

Question

I am getting a syntax error when trying to do the following MCVE in Python 3.

HEIGHT = 26
WIDTH = 26
OTHERVAR = 5

class Foo():
    def __init__(self, OTHERVAR, HEIGHT*WIDTH):
        print (str(OTHERVAR + HEIGHT*WIDTH))

foo_inst = Foo()

Below is the error

  File "a.py", line 6
    def __init__(self, OTHERVAR, HEIGHT*WIDTH):
                                       ^
SyntaxError: invalid syntax

I'm wondering why the multiplication * operator is invalid syntax in this scenario.

If someone could explain why this is bad syntax and offer a potential workaround, that would be great. Thank you.

Answer 1

A function parameter supposes to be a variable, your HEIGHT*WIDTH produces a value, not a variable.

Are you probably looking for this (default value)?

>>> a = 1
>>> b = 2
>>> def test(c=a*b):
...     print(c)
... 
>>> test()
2

>>> def test(c=a*b, d):
...     print(c, d)
... 
  File "<stdin>", line 1
SyntaxError: non-default argument follows default argument

>>> def test(d, c=a*b):
...     print(d, c)
... 
>>> test(10)
(10, 2)

And called by named parameters

>>> def test(d, c=a*b, e=20):
...     print(d, c, e)
... 
>>> test(10, e=30)
(10, 2, 30)