Hey,
In challenges the answers concerning this topics are always surprising for me.
The Python lessons are very short here.
How are class variables declared and how are instance variables declared?
Programming examples with traps&tricks are welcome.
Class variables are defined inside the class but, outside of a method's block. They are accessible to each instance of that class. For example:
class Boy:
gender = "male"
new_boy = Boy()
print(new_boy.gender) # prints "male"
So, in the above example, the "gender" is our class variable.
On the other hand, instance variable are defined inside a method of the class. They can vary with the instances. For example:
class Boy:
def __init__(self, name):
self.name = name
b1 = Boy("John")
b2 = Boy("Rahul")
b3 = Boy("Marsh")
print(b3.name) # prints "Marsh"
In the above example, "name" is our instance variable, which, as you can see, is varying with the instances!
class ClassName(object):
self.instance_variable = value #value specific to instance
class_variable = value #value shared across all class instances
#accessing instance variable
class_instance = ClassName()
class_instance.instance_variable
#accessing class variable
ClassName.class_variable
With a class you can create many objects without writing much code. Like in a factory, objects can be mass-produced. Really useful in games, when you want to create 1000 monsters from scratch.
https://code.sololearn.com/cjNkd8F0FSVB/?ref=app
class Cat:#giving class a name Cat
def __init__(self, color, legs):#def __init__ function, argument are self,color,legs. Self-it is mandatory to put self inside it for access data inside class.color&legs are of variables like name and age
self.color = color#if any function in child class contains function like Cat(x,y) x will be taken as color and y will be as legs count.
self.legs = legs
felix = Cat("ginger", 4)#here color is Ginger and leg is 4
rover = Cat("dog-colored", 4)#color will be dog-colored legs will be 4.
stumpy = Cat("brown", 3)#here color is brown and leg is 3
Very simple:p
(stumpy has 3 legs lol π)
