python class instance method call from another class instance

Question

I have a quick question regarding python classes. The following is the setup: I have one class as the "mastermind" class which contains various instances of other classes. Now these classes need to call a method of that other class, but I don't know how to do that. For example:

class mastermind(object):

    def __init__(self):
        self.hand = hand()

    def iNeedToCallThisMethod(self, funzies):
        print funzies

class hand(object):

    def __init(self):
        pass #here should be a call to the mastermind instance's method

example = mastermind()

Hope you guys can help me with that, my brain is steaming! Thanks a lot!

Peter Uhnak · Accepted Answer · 2015-04-05 23:36:14Z

9

If you want to call mastermind's method, you need to have a reference to it.

For example

class mastermind(object):
    def __init__(self):
        self.hand = hand(self)

    def iNeedToCallThisMethod(self, funzies):
        print funzies

class hand(object):
    def __init__(self, mastermind)
        mastermind.iNeedToCallThisMethod('funzies')

answered Apr 5, 2015 at 23:36

Peter Uhnak

10.3k6 gold badges42 silver badges52 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

yggdra Over a year ago

Thanks! That worked fine! But doesn't it take a lot more resources if I save the Mastermind instance into the other instance? Or is it really just a reference?

Peter Uhnak Over a year ago

In the example I've given you are not even saving the instance - the method is called on a provided parameter. But even if you did save it, it is just a reference, so there is no reason to worry about it unless you have hundreds of thousands of hands.

Saksham Varma · Accepted Answer · 2015-04-05 23:36:52Z

1

If you need to call iNeedToCallThisMethod from the __init__ of hand, you should probably put the method in that class.

However, what you want to do can be achieved using a classmethod:

class mastermind(object):
   def __init__(self):
        self.hand = hand()

   @classmethod
   def iNeedToCallThisMethod(cls, funzies):
        print funzies

class hand(object):
   def __init__(self):
        mastermind.iNeedToCallThisMethod('funzies')

example = mastermind()

answered Apr 5, 2015 at 23:36

Saksham Varma

2,14015 silver badges16 bronze badges

Comments

Malik Brahimi · Accepted Answer · 2015-04-05 23:39:43Z

-1

Both object need a reference to one another, try passing the instance to the constructor.

class Mastermind(object):

    def __init__(self):
        self.hand = Hand(self)

    def test_funct(self, arg):
        print arg


class Hand(object):

    def __init(self, mastermind):
        self.mastermind = mastermind
        self.mastermind.test_funct()

answered Apr 5, 2015 at 23:39

Malik Brahimi

16.8k7 gold badges46 silver badges76 bronze badges

Comments

JGerulskis · Accepted Answer · 2015-04-05 23:45:59Z

-1

class hand(object):

    def __init(self, other_class):
        #here should be a call to the mastermind instance's method
        other_class.iNeedToCallThisMethod()
m_m = mastermind()
example = hand(m_m) # passes mastermind to new instance of hand

I'd just pass the object like above

edited Apr 5, 2015 at 23:45

answered Apr 5, 2015 at 23:36

JGerulskis

8084 gold badges11 silver badges24 bronze badges

6 Comments

Malik Brahimi Over a year ago

You've got this all wrong, you need a reference between both object.

JGerulskis Over a year ago

Can you elaborate I believe what I posted is correct @MalikBrahimi

Alejandro Over a year ago

iNeedToCallThisMethod is an instance method, so cannot therefore be called directly using the mastermind class, as you posted. mastermind.iNeedToCallThisMethod() would only be valid for class methods and static methods.

JGerulskis Over a year ago

I believe you have mistaken that the mastermind was a call to the class mastermind but it was actually a call to a parameter being passed to the class. I should've made that clearer but the code works fine. I've changed mastermind to other_class

Alejandro Over a year ago

YES! So sorry, didn't realize that at all. The variable name threw me off

|

Collectives™ on Stack Overflow

python class instance method call from another class instance

4 Answers 4

2 Comments

Comments

Comments

6 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

Comments

Comments

6 Comments

Your Answer

Sign up or log in

Post as a guest

Related