{"id":2632,"date":"2021-10-24T14:48:17","date_gmt":"2021-10-24T14:48:17","guid":{"rendered":"https:\/\/www.pythontutorial.net\/?page_id=2632"},"modified":"2025-03-31T10:17:12","modified_gmt":"2025-03-31T10:17:12","slug":"python-overriding-method","status":"publish","type":"page","link":"https:\/\/www.pythontutorial.net\/python-oop\/python-overriding-method\/","title":{"rendered":"Python Overriding Method"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn how to use Python overriding method to allow a child class to provide a specific implementation of a method that is provided by one of its parent classes.<\/p>\n\n\n\n

Introduction to Python overriding method #<\/a><\/h2>\n\n\n\n

The overriding method allows a child class to provide a specific implementation of a method that is already provided by one of its parent classes.<\/p>\n\n\n\n

Let’s take an example to understand the overriding method better.<\/p>\n\n\n\n

First, define the Employee<\/code> class:<\/p>\n\n\n

class<\/span> Employee<\/span>:<\/span>\n    def<\/span> __init__<\/span>(self, name, base_pay)<\/span>:<\/span>\n        self.name = name\n        self.base_pay = base_pay\n\n    def<\/span> get_pay<\/span>(self)<\/span>:<\/span>\n        return<\/span> self.base_pay<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Second, define the SalesEmployee<\/code> that inherits from the Employee<\/code> class:<\/p>\n\n\n
class<\/span> SalesEmployee<\/span>(Employee)<\/span>:<\/span>\n    def<\/span> __init__<\/span>(self, name, base_pay, sales_incentive)<\/span>:<\/span>\n        self.name = name\n        self.base_pay = base_pay\n        self.sales_incentive = sales_incentive<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The SalesEmployee<\/code> class has three instance attributes: name<\/code>, base_pay<\/code>, and sales_incentive<\/code>. <\/p>\n\n\n\n
Third, create a new instance of the SalesEmployee<\/code> class and display the pay:<\/p>\n\n\n
john = SalesEmployee('John'<\/span>, 5000<\/span>, 1500<\/span>)\nprint(john.get_pay())<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
5000<\/span><\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The get_pay()<\/code> method returns only the base_pay<\/code>, not the sum of the base_pay<\/code> and sales_incentive<\/code>.  <\/p>\n\n\n\n
When you call the get_pay()<\/code> from the instance of the SalesEmployee<\/code> class, Python executes the get_pay()<\/code> method of the Employee<\/code> class, which returns the base_pay<\/code>.<\/p>\n\n\n\n
To include the sales incentive in the pay, you need to redefine the get_pay()<\/code> method in the SalesEmployee<\/code> class as follows:<\/p>\n\n\n
class<\/span> SalesEmployee<\/span>(Employee)<\/span>:<\/span>\n    def<\/span> __init__<\/span>(self, name, base_pay, sales_incentive)<\/span>:<\/span>\n        self.name = name\n        self.base_pay = base_pay\n        self.sales_incentive = sales_incentive\n\n    def<\/span> get_pay<\/span>(self)<\/span>:<\/span>\n        return<\/span> self.base_pay + self.sales_incentive<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
In this case, we say that the get_pay()<\/code> method in the SalesEmployee<\/code> class overrides the get_pay()<\/code> method in the Employee<\/code> class.<\/p>\n\n\n\n
When you call the get_pay()<\/code> method of the SalesEmployee<\/code>‘s object, Python will call the get_pay()<\/code> method in the SalesEmployee<\/code> class:<\/p>\n\n\n
john = SalesEmployee('John'<\/span>, 5000<\/span>, 1500<\/span>)\nprint(john.get_pay())<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
6500<\/span><\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
If you create an instance of the Employee<\/code> class, Python will call the get_pay()<\/code> method of the Employee<\/code> class, not the get_pay()<\/code> method of the SalesEmployee<\/code> class. For example:<\/p>\n\n\n
jane = Employee('Jane'<\/span>, 5000<\/span>)\nprint(jane.get_pay())<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Put it all together.<\/p>\n\n\n
class<\/span> Employee<\/span>:<\/span>\n    def<\/span> __init__<\/span>(self, name, base_pay)<\/span>:<\/span>\n        self.name = name\n        self.base_pay = base_pay\n\n    def<\/span> get_pay<\/span>(self)<\/span>:<\/span>\n        return<\/span> self.base_pay\n\n\nclass<\/span> SalesEmployee<\/span>(Employee)<\/span>:<\/span>\n    def<\/span> __init__<\/span>(self, name, base_pay, sales_incentive)<\/span>:<\/span>\n        self.name = name\n        self.base_pay = base_pay\n        self.sales_incentive = sales_incentive\n\n    def<\/span> get_pay<\/span>(self)<\/span>:<\/span>\n        return<\/span> self.base_pay + self.sales_incentive\n\n\nif<\/span> __name__ == '__main__'<\/span>:\n    john = SalesEmployee('John'<\/span>, 5000<\/span>, 1500<\/span>)\n    print(john.get_pay())\n\n    jane = Employee('Jane'<\/span>, 5000<\/span>)\n    print(jane.get_pay())<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Advanced method overriding example #<\/a><\/h2>\n\n\n\n
The following defines the Parser<\/code> class:<\/p>\n\n\n
class<\/span> Parser<\/span>:<\/span>\n    def<\/span> __init__<\/span>(self, text)<\/span>:<\/span>\n        self.text = text\n\n    def<\/span> email<\/span>(self)<\/span>:<\/span>\n        match = re.search(r'[a-z0-9\\.\\-+_]+@[a-z0-9\\.\\-+_]+\\.[a-z]+'<\/span>, self.text)\n        if<\/span> match:\n            return<\/span> match.group(0<\/span>)\n        return<\/span> None<\/span>\n\n    def<\/span> phone<\/span>(self)<\/span>:<\/span>\n        match = re.search(r'\\d{3}-\\d{3}-\\d{4}'<\/span>, self.text)\n        if<\/span> match:\n            return<\/span> match.group(0<\/span>)\n        return<\/span> None<\/span>\n\n    def<\/span> parse<\/span>(self)<\/span>:<\/span>\n        return<\/span> {\n            'email'<\/span>: self.email(),\n            'phone'<\/span>: self.phone()\n        }<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
The Parser<\/code> class has an attribute text<\/code> which specifies a piece of text to be parsed. Also, the Parser<\/code> class has three methods: <\/p>\n\n\n\n
The Employee<\/code> class has two instance variables<\/a> name<\/code> and base_pay<\/code>. It also has the get_pay()<\/code> method that returns the base_pay<\/code>.<\/p>\n\n\n\n