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Python Interview Questions

Python Interview Questions: Candidates who are able to answer the Python interview questions at one go to the interviewer, may find their career goal achieved at the appointment. Answering effective and relevant answers in Python interview questions create a wide opportunity for a successful interview venture. This article is composed of Python interview questionnaire. The article has been created by Aptron's Python specialists, Python experts, and Python trainers who have put their thorough experience and best of knowledge in Python interview questions and answers for freshers, and experience applicants. The questionnaire is comprises of detailed answers wrapping basic and advanced Python interview questions. The questionnaire helps job candidates to crack interviews and acknowledge relevant answers to their doubts or confusions. The Python Interview Questions is a summarization of verticals accessible in the Python technology.

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About Python

Python is an object-oriented, high-level programming language built in data structures, and combined with dynamic typing and binding. It is used as a scripting language to connect existing components together. Python is simple and easy to learn. The syntax available in Python offers program modularity, code reuse, and readability; hence reduces the cost of program maintenance. Python comes with an extensive standard library are accessible in source or binary form, which can be freely distributed. This programming language requires no compilation step and the edit-test-debug cycle is extremely fast. Debugging Python programs is simple and easy. It raises an exception by not causing a segmentation fault. When the program fails to get hold of the exception, the interpreter prints a stack trace. Python is fast and quick. It is better than C and C++ programming.

Python Interview Questions And Answers

1. What is Python? What are the benefits of using Python?

Python is a programming language with objects, modules, threads, exceptions and automatic memory management. The benefits of pythons are that it is simple and easy, portable, extensible, build-in data structure and it is an open source.

2. What is PEP 8?

PEP 8 is a coding convention, a set of recommendation, about how to write your Python code more readable.

3. What is pickling and unpickling?

Pickle module accepts any Python object and converts it into a string representation and dumps it into a file by using dump function, this process is called pickling. While the process of retrieving original Python objects from the stored string representation is called unpickling.

4. How Python is interpreted?

Python language is an interpreted language. Python program runs directly from the source code. It converts the source code that is written by the programmer into an intermediate language, which is again translated into machine language that has to be executed.

5. How memory is managed in Python?

  1. Python memory is managed by Python private heap space. All Python objects and data structures are located in a private heap. The programmer does not have an access to this private heap and interpreter takes care of this Python private heap.
  2. The allocation of Python heap space for Python objects is done by Python memory manager. The core API gives access to some tools for the programmer to code.
  3. Python also have an inbuilt garbage collector, which recycle all the unused memory and frees the memory and makes it available to the heap space.

6. What are the tools that help to find bugs or perform static analysis?

PyChecker is a static analysis tool that detects the bugs in Python source code and warns about the style and complexity of the bug. Pylint is another tool that verifies whether the module meets the coding standard.

7. What are Python decorators?

A Python decorator is a specific change that we make in Python syntax to alter functions easily.

8. What is the difference between list and tuple?

The difference between list and tuple is that list is mutable while tuple is not. Tuple can be hashed for e.g as a key for dictionaries.

9. How are arguments passed by value or by reference?

Everything in Python is an object and all variables hold references to the objects. The references values are according to the functions; as a result you cannot change the value of the references. However, you can change the objects if it is mutable.

10. What is Dict and List comprehensions are?

They are syntax constructions to ease the creation of a Dictionary or List based on existing iterable.

11. Is python case sensitive?

Yes. Python is a case sensitive language.

12. Is indentation required in python?

Indentation is necessary for Python. It specifies a block of code. All code within loops, classes, functions, etc is specified within an indented block. It is usually done using four space characters. If your code is not indented necessarily, it will not execute accurately and will throw errors as well.

13. What is self in Python?

Self is an instance or an object of a class. In Python, this is explicitly included as the first parameter. However, this is not the case in Java where it’s optional. It helps to differentiate between the methods and attributes of a class with local variables.

The self variable in the init method refers to the newly created object while in other methods, it refers to the object whose method was called.

14. What are python iterators?

Iterators are objects which can be traversed though or iterated upon.

15. What is pickling and unpickling?

Pickle module accepts any Python object and converts it into a string representation and dumps it into a file by using dump function, this process is called pickling. While the process of retrieving original Python objects from the stored string representation is called unpickling.

16. What are the generators in python?

Functions that return an iterable set of items are called generators.

17. How will you capitalize the first letter of string?

In Python, the capitalize() method capitalizes the first letter of a string. If the string already consists of a capital letter at the beginning, then, it returns the original string.

18. What is a negative index in Python?

Python sequences are accessible using an index in positive and negative numbers. For example, 0 is the first positive index, 1 is the second positive index and so on. For negative indexes -1 is the last negative index, -2 is the second last negative index and so on.

Index traverses from left to right and increases by one until end of the list.

Negative index traverse from right to left and iterate one by one till the start of the list. A negative index is used to traverse the elements into reverse order.

19. Explain docstring in Python?

The Python docstring is a string literal that occurs as the first statement in a module, function, class, or method definition. It provides a convenient way to associate the documentation.

String literals occurring immediately after a simple assignment at the top are called "attribute docstrings".

String literals occurring immediately after another docstring are called "additional docstrings".

Python uses triple quotes to create docstrings even though the string fits on one line.

Docstring phrase ends with a period (.) and can be multiple lines. It may consist of spaces and other special chars.

20. What is a generator in Python?

In Python, the generator is a way that specifies how to implement iterators. It is a normal function except that it yields expression in the function. It does not implements __itr__ and next() method and reduce other overheads as well.

If a function contains at least a yield statement, it becomes a generator. The yield keyword pauses the current execution by saving its states and then resume from the same when required.

21. What is the namespace in Python?

The namespace is a fundamental idea to structure and organize the code that is more useful in large projects. However, it could be a bit difficult concept to grasp if you're new to programming. Hence, we tried to make namespaces just a little easier to understand.

A namespace is defined as a simple system to control the names in a program. It ensures that names are unique and won't lead to any conflict.

Also, Python implements namespaces in the form of dictionaries and maintains name-to-object mapping where names act as keys and the objects as values.

22. What is the difference between append() and extend() methods?

Both append() and extend() methods are methods used for lists. These methods are used to add elements at the end of a list.

append(element): Adds the given element at the end of the list which called this method

extend(another-list): Adds the elements of another-list at the end of the list which called the extend method

23. What is lambda function in Python?

Lambda function is an anonymous function (functions that don’t have names) in Python. To define anonymous functions, we use the lambda keyword instead of the def keyword, hence the name ‘lambda function’. Lambda functions can have any number of arguments but can have only one statement.

24. What is self-keyword in Python?

Self-keyword is used as the first parameter of a function inside a class that represents the instance of the class. The object or the instance of the class is automatically passed to the method that it belongs to and is received in the ‘self-keyword’. Users can use another name for the first parameter of the function that catches the object of the class, but it is recommended to use the self-keyword only as it is more of a Python convention.

25. What do you understand by Tkinter?

Tkinter is an inbuilt Python module that is used to create GUI applications. It’s Python’s standard toolkit for GUI development. Tkinter comes with Python, so there is no installation needed. We can start using it by importing it in our script.

26. Can we make multi-line comments in Python?

Python does not have a specific syntax for including multi-line comments like other programming languages, but programmers can use triple-quoted strings (docstrings) for making multi-line comments, as when docstring is not being used as the first statement inside a method, it gets ignored by Python parser.

27. How are range and xrange different from one another?

Functions in Python, range() and xrange() are used to iterate a fixed number of times in a for loop. Functionality-wise, both of these functions are the same. Difference comes when talking about Python version support for these functions and their return values.

The range() Method The xrange() Method
In Python 3, xrange() is not supported; instead the range() function is used to iterate in for loops. The xrange() function is used in Python 2 to iterate in for loops.
It returns a list. It returns a generator object as it doesn’t really generate a static list at the run time.
It takes more memory as it keeps the entire list of iterating numbers in memory. It takes less memory as it keeps only one number at a time in memory.

28. Explain Inheritance in Python with an example.

As Python follows an object-oriented programming paradigm, classes in Python have the ability of inheriting the properties of another class. This process is known as inheritance. Inheritance provides the code reusability feature. The class that is being inherited is called a super-class and the class that inherits the other class is called a derived or child class. Following types of inheritance are supported in Python:

  1. Single inheritance: When a class inherits only one super class
  2. Multiple inheritance: When a class inherits multiple super classes
  3. Multilevel inheritance: When a class inherits a super class and then another class inherits this derived class forming a ‘parent, child, and grandchild’ class structure
  4. Hierarchical inheritance: When one super class is inherited by multiple derived classes

29. What are the supported data types in Python?

Python has five standard data types:

  • Numbers
  • Strings
  • Lists
  • Tuples
  • Dictionaries

30. What is the purpose of PYTHONPATH environment variable?

PYTHONPATH has a role similar to PATH. This variable tells Python Interpreter where to locate the module files imported into a program. It should include Python source library directory and the directories containing Python source code. PYTHONPATH is sometimes preset by Python Installer.

Career scopes and salary scale

The average unemployment is rising across job markets. But, when it is about software development and software programming, to requirement of Python programmers are at higher side. Python applicants with in-depth knowledge and skill-based training cum experience in Python programming are able find their smooth ways to achieve their career goals. Besides, Python has occupied the topmost place in the arena of programming software and application. A Python developer or programmer is expected a minimum salary of 40, 000 dollars per annum. Although the salary of an experienced Python developer can reach to double the figure mentioned before. The salaries are very dependent upon the location, business, and the company’s requirements.


The article ‘Python interview questions’ has been successfully answered every advanced Python interview questions. Additionally, the considerate structured of the Python interview questions for experienced is being designed by our trainers and team of experts. They have tried their best of knowledge to assist professionals in getting answers to all qualms and not clear concepts. Even then, if students still require more detailing about Python programming, then they may drop in a message to our experts regarding Python interview questions for experienced professionals. Our trainers would be happy to assist and resolve all your Python-programming issues of the students. Join Python Training in Noida, Python Training in Delhi, Python Training in Gurgaon

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