class variables and instance variables in Python

Question

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.

Answer 1

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!

Answer 2

Rahul your examples are very helpful!
Thanks a lot.

Answer 3

Tim aber sowas von!
Vielen Dank!

Answer 4

Some more useful tips ;)

https://code.sololearn.com/cHem7KP2mjU8/?ref=app

Answer 5

Martin very useful! danke!

Answer 6

Tim thanks for discussing your prog!

"Der klügere gibt Nachhilfe"

Answer 7

ahhh I see!
and in your program the Monsters are ronaldo, neymar and Kroos? (-:

Answer 8

https://code.sololearn.com/cyrTd1CrK27E/?ref=app

ist das hilfreich?

Answer 9

Hi guys,
i m learning python.
but ,i can't understand the 'res' operation ...pls explain me

Answer 10

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

Answer 11

siva sankar i dont even know about something that is called like this

Answer 12

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

Answer 13

What

Answer 14

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 😂)

Answer 15

What is the use of document.write

Answer 16

Hello

Answer 17

Excuse me, I don't understand the =number they put in front of variables

Answer 18

i dont know bro i am just a bigginer

Answer 19

Hey guys i don't like it

Answer 20

Глддщщ