Class with parameters python

Python Class Calling with Parameters: Best Practices and Examples

Learn how to call a class in Python with parameters and explore best practices for using classes in Python. Get examples and tips for instantiating a class, accessing variables and methods, calling base class methods, using class methods and decorators, and passing classes, functions, and modules as parameters.

• Instantiating a class with parameters
• Accessing class variables and methods
• Python Method Parameters and self
• Calling the base class method directly
• Class methods and decorators
• Passing classes, functions, and modules as parameters
• Other useful code examples for calling a Python class with parameters
• Conclusion
• How do you access parameters in a class in Python?
• Can I pass a class as a parameter in Python?
• How do you call upon a class in Python?
• How do I call a function with a parameter in Python?

Python is a popular high-level programming language that is widely used in software development and information technology. It is known for its simplicity, readability, and easy-to-learn syntax. One of the key features of Python is its support for object-oriented programming (OOP), which allows developers to encapsulate related data and functions into one unit known as a class.

In this article, we will explore how to call a class in Python with parameters. We will cover important concepts and best practices to help you better understand how to use classes in Python.

Instantiating a class with parameters

To call a function from another class with arguments from the initial class, you need to instantiate the class and pass the arguments that the __init__() method requires. The __init__() method is used to initialize the object’s attributes.

Here is an example of how to instantiate a class with parameters:

class Person: def __init__(self, name, age): self.name = name self.age = ageperson1 = Person("John", 25) print(person1.name) print(person1.age) 

In the above code snippet, we defined a class named Person that takes two parameters: name and age . We then created an instance of the class named person1 , passing in the arguments “John” and 25 to the __init__() method.

We then printed the values of the name and age attributes of the person1 object. The output of the above code snippet will be:

Accessing class variables and methods

A class contains a set of variables and a set of functions, held together as one unit. The variables are visible in all the functions in the class.

Variables defined inside the class but outside the method can be accessed within the class using the instance of the class by using self.var_name .

Here is an example of how to access class variables and methods:

class Rectangle: width = 0 height = 0 def __init__(self, width, height): self.width = width self.height = height def area(self): return self.width * self.heightrect = Rectangle(10, 20) print(rect.area()) 

In the above code snippet, we defined a class named Rectangle that takes two parameters: width and height . We then defined a method named area() that calculates the area of the rectangle.

We then created an instance of the class named rect , passing in the arguments 10 and 20 to the __init__() method.

We then called the area() method of the rect object and printed the result. The output of the above code snippet will be:

Python Method Parameters and self

Looks at the parameters of a method as defined in a class but used in an instance of the class. Duration: 11:37

Calling the base class method directly

To call the base class method directly, you can use BaseClassName.methodname(self, arguments) .

Here is an example of how to call the base class method directly:

class Vehicle: def __init__(self, name, color): self.name = name self.color = color def display_info(self): print("Name:", self.name) print("Color:", self.color)class Car(Vehicle): def __init__(self, name, color, model): super().__init__(name, color) self.model = model def display_info(self): super().display_info() print("Model:", self.model)car = Car("Toyota", "Blue", "Camry") car.display_info() 

In the above code snippet, we defined a class named Vehicle that takes two parameters: name and color . We then defined a method named display_info() that displays the name and color of the vehicle.

We then defined a subclass named Car that inherits from the Vehicle class. The Car class takes three parameters: name , color , and model . We then defined a method named display_info() that calls the display_info() method of the Vehicle class and displays the model of the car.

We then created an instance of the Car class named car , passing in the arguments “Toyota”, “Blue”, and “Camry” to the __init__() method.

We then called the display_info() method of the car object and printed the result. The output of the above code snippet will be:

Name: Toyota Color: Blue Model: Camry 

Class methods and decorators

Class methods are methods that are called on the class itself, not on a specific object instance. To call a class method, put the class as the first argument. Class methods can be called from instances and from the class itself.

You can use @staticmethod and @classmethod decorators to pass method arguments.

Here is an example of how to use class methods and decorators:

class Math: @staticmethod def add(x, y): return x + y @classmethod def multiply(cls, x, y): return cls.add(x, x) * cls.add(y, y)print(Math.add(2, 3)) print(Math.multiply(2, 3)) 

In the above code snippet, we defined a class named Math that contains two methods: add() and multiply() .

The add() method is a static method that takes two parameters and returns the sum of the two parameters.

The multiply() method is a class method that takes two parameters and calls the add() method twice, then multiplies the results.

We then called the add() and multiply() methods of the Math class and printed the results. The output of the above code snippet will be:

Passing classes, functions, and modules as parameters

Classes, functions, and modules can be passed as parameters in Python. A decorator is a callable that accepts a function or class as an argument. A label associated with a variable, a class attribute, or a function parameter or return value, used by convention as a type hint.

Here is an example of how to pass classes, functions , and modules as parameters:

class MyClass: passdef my_function(): passimport mathdef my_decorator(func): def wrapper(): print("Before function is called.") func() print("After function is called.") return wrapper@my_decorator def my_function(): print("Hello, world!")my_function() 

In the above code snippet, we defined a class named MyClass , a function named my_function() , and imported the math module.

We then defined a decorator named my_decorator() that accepts a function as an argument and returns a new function that calls the original function and adds some extra behavior.

We then decorated the my_function() function with the my_decorator() decorator and called the my_function() function.

The output of the above code snippet will be:

Before function is called. Hello, world! After function is called. 

Other useful code examples for calling a Python class with parameters

In python, class methods parameters python code example

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 #

# define class class example: # define __call__ function def __call__(self): print("It worked!") # create instance g = example() # when attempting to call instance of class it will call the __class method g() # prints It worked!