In thisPython tutorial, we will discuss the python interface and also we will check what is an interface in python with examples. Let us learn:
- What is an interface in Python?
- How to create an interface in Python?
- What is the formal and informal interface in Python?
- Python interface examples
- Python interface vs abstract class
Table of Contents
What is an Interface?
- An interface is a collection of method signatures that should be provided by the implementing class.
- An interface contains methods that are abstract in nature. The abstract methods will have the only declaration as there is no implementation.
- An interface in python is defined using python class and is a subclass of interface.Interface which is the parent interface for all interfaces.
- The implementations will be done by the classes which will inherit the interface. Interfaces in Python are a little different from other languages like Java or C# or C++.
- Implementing an interface is a way of writing an organized code.
Let us understand the Python interfaces with a few examples.
How to declare an interface in Python
Here, we will see how to declare the interface module in Python.
Syntax:
class MyInterface(zope.interface.Interface)- Firstly, we will import zope.interface module.
- The zope.interface is a module that is used to implement the object interface in python.
- The zope.interface library is the way to come out of when something is not clear.
- The interface act as a blueprint for designing classes. Here, @zope.interface.implementer(Lunch) is implemented using implementer decorator in class.
- This package export attributes and interfaces directly.
- To overcome the uncertainty of the interface zope module is implemented.
Implementation by(class) – This function returns a boolean value. If the class implements the interface it results in True else False.
Example:
import zope.interface
class Lunch(zope.interface.Interface):
northindian = zope.interface.Attribute("chocolate")
def food(self, northindian):
pass
def colddrinks(self, beverages):
pass
@zope.interface.implementer(Lunch) class Lunch(zope.interface.Interface):
def food(self, northindian):
return northindian
def colddrinks(self,beverages):
return beverages
colddrinks = Lunch['colddrinks']
food = Lunch['food']
print(Lunch.implementedBy(Lunch))
print(type(colddrinks))
print(type(food))
See AlsoPython Classes and InterfacesHere, we can see that the class is implemented in the interface. So, the boolean value true is returned. Also, we can see the output two times the <class ‘zope.interface.interface.Method’> is returned because I have defined two functions def food and def colddrinks in a class.
Below image shows the output:
Create a Python interface
There are two ways for creating and implementing the interface in python are –
- Informal Interface
- Formal Interface
Informal interface in python
An informal interface in Python is a class. It defines methods that can be overridden but without force enforcement. An informal interface in python is termed as a protocol because it is informal and cannot be enforced formally. The commonly used methods which are used to perform some operations are:
- __iter__ – This method returns an iterator for an object.
- __len__ – This method returns the length of string, list, dictionary, tuple.
- __contain__ – This method used to check whether it contains another string.
Example:
class Chocolate: def __init__(self, items): self.__items = items def __len__(self): return len(self.__items) def __contains__(self, items): return items in self.__itemsfav_chocolate = Chocolate(["kitkat", "diarymilk", "munch","5star"])print(len(fav_chocolate))print("kitkat" in fav_chocolate)print("munch" not in fav_chocolate)print("dirymilk" not in fav_chocolate)print("5star" in fav_chocolate)- In this example, I have implemented __len__ and __contain__. We can directly use the len() function on the chocolate instance, then we have to check for an item whether it is present in the list.
- Using in operator, print(len(fav_chocolate)) used to find the length of the list.
- Here, we can see that it returns a boolean value. If the item is present in the list it will return true else it will return false. Below screenshot shows the output:
Formal interface in python(ABCs)
Here, we can see formal interface in python.
- A formal interface is an interface which enforced formally. For creating a formal interface we need to use ABCs(Abstract Base Classes).
- The ABCs is explained as we define a class that is abstract in nature, we also define the methods on the base class as abstract methods.
- Any object we are deriving from the base classes is forced to implement those methods.
- In this example, I have imported a module abc and defined a class Food. The @abc.abstractmethod is a decorator indicating abstract methods this is used to declare abstract methods for properties.
- I have defined a function def taste using the def keyword, by using the self keyword we can access the attributes and methods of the class.
- And, I have also defined a subclass as class north_indian and then printing an instance from the class food. The pass statement is used as a placeholder.
Example:
import abcclass Food (abc.ABC): @abc.abstractmethod def taste( self ): passclass north_indian(Food) : def taste(self): print(" Cooking! ")s = north_indian ()print( isinstance(s, Food))Below screenshot shows the output:
In this output, we can see that output a boolean value. It returns true only if the instance is present in the class else it returns false.
Python interface examples
Here, we will see how code for derived class defines an abstract method. So, we have imported abc module and we have the class name as myinterface(abc.ABC).
Example:
import abcclass myinterface(abc.ABC): @abc.abstractclassmethod def display(): passprint("This is Myclass")class Myclass(myinterface): def display(): passobj=Myclass()Here, obj = Myclass() is called and it prints the output as “This is Myclass”. You can refer to the below screenshot for python interface examples.
Python multiple interfaces
Now, we can see multiple interfaces in Python.
In the below example, we have to import abc module, and then we can initialize the class as Food and subclass as northIndian() and southIndian().
Example:
import abcclass Food (abc.ABC): @abc.abstractmethod def taste( self ): passclass northIndian(Food) : def taste(self): print(" Cooking! ")class Food (abc.ABC): @abc.abstractmethod def taste(self): passclass southIndian(Food) : def taste(self) : print(" Cooking!.. ")a = northIndian ()s = southIndian()print( isinstance(s, northIndian))print( isinstance(s, southIndian))print( isinstance(a, northIndian))print( isinstance(a, southIndian))Here, we can see in the output as false because instance s is assigned to southIndian but in a print statement, it is assigned as (s, northIndian). We can refer to the below screenshots:
Python interface vs abstract class
Let us understand the difference between Python interface vs abstract class.
| Python interface | Python abstract class |
| An interface is a set of methods and attributes on that object. | We can use an abstract base class to define and enforce an interface. |
| All methods of an interface are abstract | An abstract class can have abstract methods as well as concrete methods. |
| We use an interface if all the features need to be implemented differently for different objects. | Abstract classes are used when there is some common feature shared by all the objects as they are. |
| The interface is slow as compared to the abstract class. | Abstract classes are faster. |
You may like the following Python tutorials:
- How to convert a String to DateTime in Python
- Escape sequence in Python
- Python list comprehension lambda
- Python Threading and Multithreading
- How to convert Python degrees to radians
- Python Comparison Operators
- Python namespace tutorial
- Linked Lists in Python
In this Python tutorial, we have learned about the Python interface. Also, We covered these below topics:
- What is an Interface?
- How to Declare an interface in Python
- How to create an interface in Python
- Python interface examples
- Python multiple interfaces
- Python interface vs abstract class
Bijay Kumar
Python is one of the most popular languages in the United States of America. I have been working with Python for a long time and I have expertise in working with various libraries on Tkinter, Pandas, NumPy, Turtle, Django, Matplotlib, Tensorflow, Scipy, Scikit-Learn, etc… I have experience in working with various clients in countries like United States, Canada, United Kingdom, Australia, New Zealand, etc. Check out my profile.
FAQs
What is Python interface? ›
Python Interface Overview
At a high level, an interface acts as a blueprint for designing classes. Like classes, interfaces define methods. Unlike classes, these methods are abstract. An abstract method is one that the interface simply defines. It doesn't implement the methods.
In object-oriented languages like Python, the interface is a collection of method signatures that should be provided by the implementing class. Implementing an interface is a way of writing an organized code and achieve abstraction.
What is the difference between Python interface and Python abstract class? ›An abstract class can contain both abstract and non-abstract methods, whereas an Interface can have only abstract methods. Abstract classes are extended, while Interfaces are implemented.
What is the difference between class and interface in Python? ›In a more basic way to explain: An interface is sort of like an empty muffin pan. It's a class file with a set of method definitions that have no code. An abstract class is the same thing, but not all functions need to be empty. Some can have code.
What are the 3 types of interfaces? ›graphical user interface (GUI) command line interface (CLI) menu-driven user interface.
What are the 4 types of interfaces? ›- Command Line Interface.
- Menu-driven Interface.
- Graphical User Interface.
- Touchscreen Graphical User Interface.
Interfaces are not natively supported by Python, although abstract classes and abstract methods can be used to go around this. At a higher perspective, an interface serves as a template for class design. Interfaces create methods in the same way that classes do, but unlike classes, these methods are abstract.
Which interface is best for Python programming? ›- PyQt5. Developed by Riverbank Computing, PyQt5 is one of the most popular Python frameworks for GUI. ...
- Tkinter. Another top Python library for GUI is Tkinter, which is an open-source Python Graphic User Interface library. ...
- Kivy. ...
- wxPython. ...
- PySimpleGUI. ...
- Libavg. ...
- PyForms. ...
- PySide2.
Unfortunately, Python doesn't have interfaces, or at least, not quite built into the language. Enter Python's abstract base class, or, cutely, ABC. Functionally, abstract base classes let you define a class with abstract methods, which all subclasses must implement in order to be initialized.
Why should you use an abstract class vs an interface? ›The short answer: An abstract class allows you to create functionality that subclasses can implement or override. An interface only allows you to define functionality, not implement it. And whereas a class can extend only one abstract class, it can take advantage of multiple interfaces.
Should I use abstract class or interface? ›
If you are creating functionality that will be useful across a wide range of objects, then you must use an interface. Abstract classes, at the end of the day, should be used for objects that are closely related. But the interfaces are best suited for providing common functionality to unrelated cases.
Why are interfaces better than abstract classes? ›Differences between abstract classes and interfaces. From an object-oriented programming perspective, the main difference between an interface and an abstract class is that an interface cannot have state, whereas the abstract class can have state with instance variables.
Why are interfaces better than classes? ›An interface defines common functionality across unrelated classes. For example, all sorts of classes that look nothing like each other may have the need to safely get rid of the resources they use. The IDisposable interface (the name for it in . NET) defines a Dispose() method, which classes then implement.
How can we implement interface in Python? ›Unfortunately, Python doesn't have interfaces, or at least, not quite built into the language. Enter Python's abstract base class, or, cutely, ABC. Functionally, abstract base classes let you define a class with abstract methods, which all subclasses must implement in order to be initialized.
Is module and interface same? ›A module is used to specify the functionality of the logic. For example if you are building a counter you would use a module to define the functionality (up behavior/down behavior/reset behavior) of the counter. An interface as the name suggests is used to specify the interface behaviour.
What are the 5 parts of interface? ›- 5 fundamental elements of interface design. How components like language, colour, imagery, typography, and icons work in the context of a user interface. ...
- Language. There are various ways we can work with words within our project: ...
- Colour. ...
- Imagery. ...
- Typography. ...
- Icons.
- command line (cli)
- graphical user interface (GUI)
- menu driven (mdi)
- form based (fbi)
- natural language (nli)
In conclusion, we explained the 5 main types of user interfaces. We talked about Graphical User Interface (GUI), Command Line Interface (CLI), Natural Language Interface (NLI), Menu-driven Interface and Form-based Interface. Also, we discussed examples for the types of user interfaces so that it is easy to relate.
What are the 6 principles of interface design? ›The 6 principles of user interface design are Structure, Simplicity, Visibility, Feedback, Tolerance and Reuse.
What is the most popular interface? ›GUI is one of the most popular and simple interfaces.
What are interfaces examples? ›
An interface is a description of the actions that an object can do... for example when you flip a light switch, the light goes on, you don't care how, just that it does. In Object Oriented Programming, an Interface is a description of all functions that an object must have in order to be an "X".
Are interfaces necessary in Python? ›Interfaces are not necessary in Python. This is because Python has proper multiple inheritance, and also ducktyping, which means that the places where you must have interfaces in Java, you don't have to have them in Python. That said, there are still several uses for interfaces.
What is the advantage of interface in Python? ›The interfaces allow the functions or methods to limit the range of acceptable parameter objects that implement a given interface, no matter what kind of class it comes from. This allows for more flexibility than restricting arguments to given types or their subclasses.
Which interface is best for beginners? ›- Focusrite Scarlett 2i2 3rd Gen. Quick Look. ...
- Focusrite Scarlett 4i4. Quick Look. ...
- Behringer U-phoria 204HD. Quick Look. ...
- Presonus Audiobox USB 96. Quick Look. ...
- Native Instruments Komplete Audio 2. Quick Look. ...
- Mackie Onyx Producer 2.2. Quick Look. ...
- Audient iD4 MKII USB-C Audio Interface.
The two most popular IDEs for beginner Python developers are IDLE and Pythonista. IDLE is a very simple IDE included with the Python standard library, and Pythonista is a more full-featured IDE that consists of a code editor, debugger, and interactive shell.
Can you make a nice GUI with Python? ›Creating a simple graphical user interface (GUI) that works across multiple platforms can be complicated. But it doesn't have to be that way. You can use Python and the PySimpleGUI package to create nice-looking user interfaces that you and your users will enjoy!
What are the types of interface methods? ›The interface body can contain abstract methods, default methods, and static methods. An abstract method within an interface is followed by a semicolon, but no braces (an abstract method does not contain an implementation).
What is interfaces and its types? ›Interfaces are tools and concepts that technology developers use as points of interaction between hardware and software components. They help all components within a system communicate with each other via an input-output system and detailed protocols while also allowing them to function independently.
What is a real life example of interface? ›The Interface is a medium to interact between user and system devices. For example, in our real life, if we consider the interface to be given as an example is the air condition, bike, ATM machine, etc.
When would you use an interface over a class? ›When should we use classes and interfaces? If you want to create and pass a type-checked class object, you should use TypeScript classes. If you need to work without creating an object, an interface is best for you.
Why would you use an interface? ›
Interfaces are useful for the following: Capturing similarities among unrelated classes without artificially forcing a class relationship. Declaring methods that one or more classes are expected to implement. Revealing an object's programming interface without revealing its class.
Is interface better than inheritance? ›We can inherit enormously more classes than Inheritance, if we use Interface. Methods can be defined inside the class in case of Inheritance. Methods cannot be defined inside the class in case of Interface (except by using static and default keywords). It overloads the system if we try to extend a lot of classes.
How many interfaces can a class implement? ›One class can implement any number of interfaces, allowing a single class to have multiple behaviors.
How do you declare an interface? ›The Interface Declaration
Two elements are required in an interface declaration — the interface keyword and the name of the interface. The public access specifier indicates that the interface can be used by any class in any package.
An interface can't be instantiated directly. Its members are implemented by any class or struct that implements the interface. A class or struct can implement multiple interfaces.
Can we create an object of an interface? ›Like abstract classes, interfaces cannot be used to create objects (in the example above, it is not possible to create an "Animal" object in the MyMainClass) Interface methods do not have a body - the body is provided by the "implement" class. On implementation of an interface, you must override all of its methods.
What are default methods in interface? ›Default methods enable you to add new functionality to existing interfaces and ensure binary compatibility with code written for older versions of those interfaces. In particular, default methods enable you to add methods that accept lambda expressions as parameters to existing interfaces.
What is difference between abstraction and interface? ›The Abstract class and Interface both are used to have abstraction. An abstract class contains an abstract keyword on the declaration whereas an Interface is a sketch that is used to implement a class.
What is the difference between model and interface? ›The Interface describes either a contract for a class or a new type. It is a pure Typescript element, so it doesn't affect Javascript. A model, and namely a class, is an actual JS function which is being used to generate new objects.
What is the difference between constructor and interface? ›A Constructor is a special member function used to initialize the newly created object. It is automatically called when an object of a class is created. Why interfaces can not have the constructor? An Interface is a complete abstraction of class.
How are interfaces implemented? ›
To declare a class that implements an interface, you include an implements clause in the class declaration. Your class can implement more than one interface, so the implements keyword is followed by a comma-separated list of the interfaces implemented by the class.
Is a bus an interface? ›The bus in a PC is the common hardware interface between the CPU and peripheral devices.
What do you mean by an interface? ›: a surface forming a common boundary of two bodies, spaces, or phases. an interface between oil and water. : the place at which independent systems meet and act on or communicate with each other. : the ways by which interaction or communication is brought about at an interface.
Is there a Python interface? ›Unfortunately, Python doesn't have interfaces, or at least, not quite built into the language. Enter Python's abstract base class, or, cutely, ABC. Functionally, abstract base classes let you define a class with abstract methods, which all subclasses must implement in order to be initialized.
What is the best interface for Python? ›- PyQt5. Developed by Riverbank Computing, PyQt5 is one of the most popular Python frameworks for GUI. ...
- Tkinter. Another top Python library for GUI is Tkinter, which is an open-source Python Graphic User Interface library. ...
- Kivy. ...
- PySimpleGUI. ...
- Libavg. ...
- PyForms. ...
- PySide2. ...
- Wax.
...
Tkinter Programming
- Import the Tkinter module.
- Create the GUI application main window.
- Add one or more of the above-mentioned widgets to the GUI application.
- Enter the main event loop to take action against each event triggered by the user.
Python Tkinter
Tkinter is the standard built-in GUI library for Python, and, with over 41,000 stars on GitHub, it's the most popular Python GUI framework. It's a fast and easy-to-use Python GUI library, making it the go-to library for building a Python GUI application.
Recommended audio interfaces for beginners
The Focusrite Scarlett 4i4* is among the most popular USB audio interfaces and it's now available in its third generation. It's known for its good sound, practical set of features, and attractive price.
Compared to some other GUI frameworks, PyGUI is by far the simplest and lightweight of them all, as the API is purely in sync with Python. PyGUI inserts very less code between the GUI platform and Python application, hence the display of the application usually displays the natural GUI of the platform.
What are the 5 types of interface? ›- command line (cli)
- graphical user interface (GUI)
- menu driven (mdi)
- form based (fbi)
- natural language (nli)
What is the main purpose of an interface? ›
Interfaces are useful for the following: Capturing similarities among unrelated classes without artificially forcing a class relationship. Declaring methods that one or more classes are expected to implement. Revealing an object's programming interface without revealing its class.
What are the steps in creating the interface? ›- Research.
- Use cases.
- Interface structure.
- Interface prototyping.
- Defining of stylistics.
- Design concept.
- Designing of all screens.
- Interface animation.
An interface is declared by using the interface keyword. It provides total abstraction; means all the methods in an interface are declared with the empty body, and all the fields are public, static and final by default. A class that implements an interface must implement all the methods declared in the interface.