class methods in python

#To create a static method, just add "@staticmethod" before defining it.

>>>class Calculator:
    # create static method
    @staticmethod
    def multiplyNums(x, y):
        return x * y

>>>print('Product:', Calculator.multiplyNums(15, 110))
Product:1650

class MyClass(object):
  def __init__(self, x):
    self.x = x

class Box(object): #(object) ending not required
  def __init__(self, color, width, height): # Constructor: These parameters will be used upon class calling(Except self)
    self.color = color # self refers to global variables that can only be used throughout the class
    self.width = width
    self.height = height
    self.area = width * height
  def writeAboutBox(self): # self is almost always required for a function in a class, unless you don't want to use any of the global class variables
    print(f"I'm a box with the area of {self.area}, and a color of: {self.color}!")

greenSquare = Box("green", 10, 10) #Creates new square
greenSquare.writeAboutBox() # Calls writeAboutBox function of greenSquare object

@classmethod
def func(cls, args...)

from datetime import date

# random Person
class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    @classmethod
    def fromBirthYear(cls, name, birthYear):
        return cls(name, date.today().year - birthYear)

    def display(self):
        print(self.name + "'s age is: " + str(self.age))

person = Person('Adam', 19)
person.display()

person1 = Person.fromBirthYear('John',  1985)
person1.display()

# Python program to 
# demonstrate instantiating 
# a class 
  
  
class Dog:  
      
    # A simple class 
    # attribute 
    attr1 = "mamal"
    attr2 = "dog"
  
    # A sample method   
    def fun(self):  
        print("I'm a", self.attr1) 
        print("I'm a", self.attr2) 
  
# Driver code 
# Object instantiation 
Rodger = Dog() 
  
# Accessing class attributes 
# and method through objects 
print(Rodger.attr1) 
Rodger.fun() 

class Animal(object): # Doesn't need params but put it there anyways.
    def __init__(self, species, price):
        self.species = species # Sets species name
        self.price = price # Sets price of it
    
    def overview(self): # A function that uses the params of the __init__ function
        print(f"This species is called a {self.species} and the price for it is {self.price}")

class Fish(Animal): # Inherits from Animal
    pass # Don't need to add anything because it's inherited everything from Animal
 
salmon = Fish("Salmon", "$20") # Make a object from class Fish
salmon.overview() # Run a function with it
dog = Animal("Golden retriever", "$400") # Make a object from class Animal
dog.overview() # Run a function with it

class Float:
    def __init__(self, amount):
        self.amount = amount

    def __repr__(self):
        return f'<Float {self.amount:.3f}>'

    @classmethod
    def from_sum(cls, value_1, value_2):
        return cls(value_1 + value_2)


class Dollar(Float):
    def __init__(self, amount):
        super().__init__(amount)
        self.symbol = '€'

    def __repr__(self):
        return f'<Euro {self.symbol}{self.amount:.2f}>'


print(Dollar.from_sum(1.34653, 2.49573)) 

class Foo          (object):
    # ^class name  #^ inherits from object

    bar = "Bar" #Class attribute.

    def __init__(self):
        #        #^ The first variable is the class instance in methods.  
        #        #  This is called "self" by convention, but could be any name you want.
        #^ double underscore (dunder) methods are usually special.  This one 
        #  gets called immediately after a new instance is created.

        self.variable = "Foo" #instance attribute.
        print self.variable, self.bar  #<---self.bar references class attribute
        self.bar = " Bar is now Baz"   #<---self.bar is now an instance attribute
        print self.variable, self.bar  

    def method(self, arg1, arg2):
        #This method has arguments.  You would call it like this:  instance.method(1, 2)
        print "in method (args):", arg1, arg2
        print "in method (attributes):", self.variable, self.bar


a = Foo() # this calls __init__ (indirectly), output:
                 # Foo bar
                 # Foo  Bar is now Baz
print a.variable # Foo
a.variable = "bar"
a.method(1, 2) # output:
               # in method (args): 1 2
               # in method (attributes): bar  Bar is now Baz
Foo.method(a, 1, 2) #<--- Same as a.method(1, 2).  This makes it a little more explicit what the argument "self" actually is.

class Bar(object):
    def __init__(self, arg):
        self.arg = arg
        self.Foo = Foo()

b = Bar(a)
b.arg.variable = "something"
print a.variable # something
print b.Foo.variable # Foo

# Python CLASSMETHOD 
  
class Subject: 
      
    # create a variable 
    favorite_subject = "Networking"
      
    # create a function 
    def favorite_subject_name(obj): 
        print("My favorite_subject_name is : ", 
                           obj.favorite_subject) 
          
# create favorite_subject_name classmethod 
# before creating this line favorite_subject_name() 
# It can be called only with object not with class 
Subject.favorite_subject_name = classmethod(Subject.favorite_subject_name) 
  
# now this method can be called as classmethod 
# favorite_subject_name() method is called as class method 
Subject.favorite_subject_name() 

>>> class Snake:
...     pass
... 
>>> snake = Snake()
>>> print(snake)
<__main__.Snake object at 0x7f315c573550>