Python Slots Vs Data Class

3/17/2022

Python Class Data Type
Python Slots Vs Data Classic

Python Classes/Objects

Python is an object oriented programming language.

Almost everything in Python is an object, with its properties and methods.

Data classes are just regular classes that are geared towards storing state, more than contain a lot of logic. Every time you create a class that mostly consists of attributes you made a data class.

Python Objects and Classes. Python is an object oriented programming language. Unlike procedure oriented programming, where the main emphasis is on functions, object oriented programming stresses on objects. An object is simply a collection of data (variables) and methods (functions) that act on those data.
使用slots 但是，如果我们想要限制class的属性怎么办？比如，只允许对Student实例添加name和age属性。为了达到限制的目的，Python允许在定义class的时候，定义一个特殊的slots变量，来限制该class能添加的属性： class Student(object).

A Class is like an object constructor, or a 'blueprint' for creating objects.

Create a Class

To create a class, use the keyword class:

Example

Create a class named MyClass, with a property named x:

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Create Object

Now we can use the class named MyClass to create objects:

Example

Create an object named p1, and print the value of x:

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The init() Function

The examples above are classes and objects in their simplest form, and are not really useful in real life applications.

To understand the meaning of classes we have to understand the built-in __init__() function.

All classes have a function called __init__(), which is always executed when the class is being initiated.

Use the __init__() function to assign values to object properties, or other operations that are necessary to do when the object is being created:

Example

Create a class named Person, use the __init__() function to assign values for name and age:

class Person:
def __init__(self, name, age):
self.name = name
self.age = age
p1 = Person('John', 36)
print(p1.name)
print(p1.age)

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Note: The __init__() function is called automatically every time the class is being used to create a new object.

Object Methods

Objects can also contain methods. Methods in objects are functions that belong to the object.

Let us create a method in the Person class:

Example

Insert a function that prints a greeting, and execute it on the p1 object:

class Person:
def __init__(self, name, age):
self.name = name
self.age = age
def myfunc(self):
print('Hello my name is ' + self.name)
p1 = Person('John', 36)
p1.myfunc()

Try it Yourself » Python slots vs data classifications

Note: The self parameter is a reference to the current instance of the class, and is used to access variables that belong to the class.

The self Parameter

The self parameter is a reference to the current instance of the class, and is used to access variables that belongs to the class.

It does not have to be named self , you can call it whatever you like, but it has to be the first parameter of any function in the class:

Example

Use the words mysillyobject and abc instead of self:

With__slots__:

The second piece of code will reduce the burden on your RAM. Some peoplehave seen almost 40 to 50% reduction in RAM usage by using thistechnique.

On a sidenote, you might want to give PyPy a try. It does all of theseoptimizations by default.