Since I first laid my eyes upon a Class I have felt intimidated. In the few occurrences that I did come across a Class in Python it has always looked complex and convoluted.
Here is a clear example of what is usually presented:
Class Student:
school_name = 'ABC School'
def __init__ (self, name, age): +
self.name = name
self.age = age
def change school (cls, name):
print (Student. school_name)
Student. school_name = name
jessa = Student (' Jessa', 14)
Student. change_school (' XYZ School')
To a newbie like myself, this is too much. Even when the vocabulary is explained, it is not intuitive.
Personally I would say 2 things make Classes extra difficult to understand: __init__ above, and (self) or self.example.
No me gusta!
Let’s start from scratch, forget that bogus example above. Let me talk about the 2 cars that I have owned. Now, people tell me I have a taste for the high life as they say. My first car was named “Pegasus”, it was a white 2003 Toyota Camry. A chariot fit for a king. My second car is called “Jazzy”, a white 2011 Honda Jazz(Fit in USA). She is a smooth operator if I do say so myself.
Now each car has specific details that belong to it. Let’s call these cars Objects. In Python an object can be described as a collection of properties which can be expressed as variables or functions.
car1 car2
name: Pegasus Jazzy
color: White White
year: 2003 2011
model: Camry Jazz
make: Toyota Honda
Notice how each car(object) has the same exact type of attributes but different values. The blueprint in which you can make these objects is called a Class. When you want to make an object you want to know what kind of attributes, properties, and functions it will have. A Class can be used to specify all of that.
I could begin writing the objects like so …
Class Car:
def introduce_self(self):
print("I am " + self.name)
car1 = Car()
car1.name = 'Pegasus'
car1.color = 'White'
car1.year = 2003
car1.model = 'Camry'
car1.make = 'Toyota'
#This will produce
#"I am Pegasus"
Now writing car1.detail = something or car2.detail = something else can get tiresum. What if there was a way to create that object with all of that information at once? You can use a constructor __init__ to put the information as an argument into that Class. Let me provide you with an example.
Class Car:
def __init__(self, putName, putColor, putYear, putModel, putMake):
self.name = putName # most people don't place the "put" in their classes
self.color = putColor # I just placed "put" there to highlight that is where you place
self.year = putYear # your information, it usually looks like:
self.model = putModel # def __init__(self, ...., make)
self.make = putMake # self.make = make
def introduce_self(self):
print("I am " + self.name)
#this code no longer works
# car1 = Car()
# car1.name = 'Pegasus'
# car1.color = 'White'
# car1.year = 2003
# car1.model = 'Camry'
# car1.make = 'Toyota'
#Now we have to use This
car1 = Car("Pegasus", "White", 2003, "Camry", "Toyota")
car2 = Car("Jazzy", "White", 2011, "Jazz", "Honda")
#and you can use something like
car2.introduce_self()
#to print
#"I am Jazzy"
The Class is useful to create and store the information of objects. The reason “self” shows up everywhere is because Python does not use special syntax to refer to object attributes.
The other parts that can cause confusion is in a Class:
variables –> properties
functions –> methods
and an object is more or less an instance.
Hopefully this clarifies Classes for you. I know it did for me.
Adios,
Merl