Changing a variable's value inside a class in python

Question

I have a variable:

var_1 = 5

I pass it to a class:

class x():
    def __init__(self, val):
        self.class_var_1 = val

object_1 = x(var_1)

I want to change var_1's value using class x, but it won't change

object_1.class_var_1 = 3

print var_1
5

var_1 isn't copied to object_1.class_var_1 with a reference to var_1.

How do I change var_1's value by changing object_1.class_var_1's value?

You can't. Integers are immutable.

anon582847382
– anon582847382

2014-04-16 10:40:05 +00:00
Commented Apr 16, 2014 at 10:40 — anon582847382
– anon582847382, Commented Apr 16, 2014 at 10:40

David Heffernan · Accepted Answer · 2014-04-16 10:41:55Z

2

Python int is immutable. The object can never change its value. Thus you need to re-bind the name to a different object. You'll need code like this:

var_1 = ...

Substitute whatever you like on the right hand side.

answered Apr 16, 2014 at 10:41

David Heffernan

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11 Comments

alwbtc Over a year ago

Ok, what if it is not a int but a bool?

David Heffernan Over a year ago

If you are interested in booleans, why did you ask about int. But as it happens, Python booleans are also immutable.

alwbtc Over a year ago

I didnt know it would matter.

anon582847382 Over a year ago

@alwbtc Booleans are immutable as well.

Samy Arous Over a year ago

you can use a mutable object like a list (even if it contains one single int) or a custom object.

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