CODEWITHSUNDEEP
pythonclassmethodstypes
Owen Mehta-Jones
Owen Mehta-Jones

Reputation: 11

Python class return types

I was wondering if anyone could help me with something. If I have a class that has an attribute is there a way to automatically make an object of that class return that attribute whenever it is called

class Constant():
def __init__(self, value):
    self.__value = value
PI = Constant(3.14)

Is there any way for it to return 3.14 (as an actual float not a string) without explicitly defining the __float__ method and calling float(PI). I want to be able to just say something along the lines of print(PI*2) and to get 6.28 as my output

EDIT: I found what I wanted, by using the __new__ method i can change the return value from an instance to whatever I want.

2nd EDIT: turns out that didn't work.

Upvotes: 1

Views: 2765

Answers (2)

U13-Forward
U13-Forward

Reputation: 71560

Try subclassing float:

class Constant(float):
    def __init__(self, value):
        self.__value = value
PI = Constant(3.14)
print(PI*2)

Output:

6.28

Upvotes: 4

Arun Augustine
Arun Augustine

Reputation: 1766

Try this for accessing a private variable 

class Constant():
    def __init__(self, value):
        self.__value = value

PI = Constant(3.14)
print(PI._Constant__value*2)


6.28

Upvotes: 1

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