why do we put () while calling some function and some we don't in python?

Question

df.shape #we check the shape of dataset
(1338, 7)

While calling the above shape function, we did not use () but for most of the other function we use (). why is that?

df.info()# gives the info of the dataset 

Answer 1

pandas.DataFrame.shape is not a function, it's a property, as you can see here in the definition of shape:

    @property
    def shape(self) -> Tuple[int, int]:
        ...

A property is accessed (read and written) just as if it were a regular attribute of the object, so no parentheses are used.