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Python classes and objects

In Python, classes and objects are used to group related variables into a single unit.^[400-devops__09-Scripting-Language__python__introduction__README.md] This is useful when managing data entities that have multiple properties, such as a customer with a first name, last name, and ID, rather than storing them as simple strings.^[400-devops__09-Scripting-Language__python__introduction__README.md]

Classes

A class serves as a blueprint for creating data structures.^[400-devops__09-Scripting-Language__python__introduction__README.md] It defines the attributes (variables) and methods (functions) that the instantiated objects will possess.^[400-devops__09-Scripting-Language__python__introduction__README.md]

Methods

Methods are functions defined within a class that operate on the object's data.^[400-devops__09-Scripting-Language__python__introduction__README.md] For example, a fullName() method within a Customer class can concatenate the firstName and lastName attributes.^[400-devops__09-Scripting-Language__python__introduction__README.md]

The Constructor

The __init__ method is a special method known as the constructor.^[400-devops__09-Scripting-Language__python__introduction__README.md] It allows new objects to be initialized with specific values immediately upon creation, rather than setting each attribute individually after the object is created.^[400-devops__09-Scripting-Language__python__introduction__README.md]

Objects

An object is an instance of a class.^[400-devops__09-Scripting-Language__python__introduction__README.md] Once an object is created (instantiated), it contains the actual data defined by the class structure.^[400-devops__09-Scripting-Language__python__introduction__README.md] You can access the object's data and methods using dot notation (e.g., object.attribute).^[400-devops__09-Scripting-Language__python__introduction__README.md]

Example Usage

The following example demonstrates defining a class with a constructor and a method, creating an instance of it, and using the method:

class Customer:
  def __init__(self, c="", f="", l=""):
    self.customerID = c
    self.firstName  = f
    self.lastName   = l

  def fullName(self):
    return self.firstName + " " + self.lastName

# Creating an object (instance)
marcel = Customer("h", "Marcel", "Dempers")

# Accessing functionality
print(marcel.fullName())

^[400-devops__09-Scripting-Language__python__introduction__README.md]

  • [[Functions]]
  • [[Dictionaries]]
  • [[Object-oriented programming]]

Sources

  • 400-devops__09-Scripting-Language__python__introduction__README.md