TOP 25 PYTHON INTERVIEW QUESTIONS & ANSWERS - 2020

1. What is python?
   

Python is a high-level, interpreted, interactive and object-oriented scripting language. Python is designed to be highly readable. It uses English keywords frequently whereas other languages use punctuation, and it has fewer syntactic constructions than other languages.

2. What are the key features of Python?

Ans: 

If it makes for an introductory language to programming, Python must mean something. These are its qualities:

• Interpreted

• Dynamically-typed

• Object-oriented

• Concise and simple

• Free and open source

• Has a large community

3. What is PEP 8?

Ans: 

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

4. What is the purpose of the PYTHONPATH environment variable?

Ans: 

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

5. What is pickling and unpickling?

Ans: 

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

6. How is Python interpreted?

Ans: 

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.

7. What is the purpose of the PYTHONSTARTUP environment variable?

Ans: 

PYTHONSTARTUP - It contains the path of an initialization file containing Python source code. It is executed every time you start the interpreter. It is named as .pythonrc.py in Unix and it contains commands that load utilities or modify PYTHONPATH.

8. How memory is managed in Python?

Ans: 

• 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 access to this private heap and the interpreter takes care of this Python private heap.

• The allocation of Python heap space for Python objects is done by the Python memory manager. The core API gives access to some tools for the programmer to code.

• Python also has an inbuilt garbage collector, which recycles all the unused memory and frees the memory and makes it available to the heap space.

9. What is the purpose of the PYTHONCASEOK environment variable?

Ans: 

PYTHONCASEOK − It is used in Windows to instruct Python to find the first case-insensitive match in an import statement. Set this variable to any value to activate it.

10. What is the purpose of the PYTHONHOME environment variable?

Ans: 

PYTHONHOME − It is an alternative module search path. It is usually embedded in the PYTHONSTARTUP or PYTHONPATH directories to make switching module libraries easy.

11. Is python a case sensitive language?

Ans: 

Yes! Python is a case sensitive programming language.

12. What are the supported data types in Python?

Ans: 

Python has five standard data types −

• Numbers

• String

• List

• Tuple

• Dictionary

• Set

13. What are the built-in types does python provide?

Ans: 

There are mutable and Immutable types of Pythons built-in types Mutable built-in types

• List

• Sets

• Dictionaries

Immutable built-in types

• Strings

• Tuples

• Numbers

• Frozen set

14. What are tuples in Python?

Ans: 

• A tuple is another sequence data type that is similar to the list. A tuple is a sequence of immutable Python objects. A tuple consists of some values separated by commas. Unlike lists, however, tuples are enclosed within parentheses.

15. What are Python's dictionaries?

Ans: 

Python's dictionaries are a kind of hash table type. They work like associative arrays or hashes found in Perl and consist of key-value pairs. A dictionary key can be almost any Python type but are usually numbers or strings. Values, on the other hand, can be any arbitrary Python object.

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

Ans: 

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.

17. What are Python decorators?

Ans: 

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

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

Ans: 

Everything in Python is an object and all variables hold references to the objects. The reference 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.

19. What is Dict and List comprehension?

Ans: 

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

20. What is namespace in Python?

Ans: 

In Python, every name introduced has a place where it lives and can be hooked for. This is known as a namespace. It is like a box where a variable name is mapped to the object placed. Whenever the variable is searched out, this box will be searched, to get the corresponding object.

21. What is lambda in Python?

Ans: 

It is a single expression anonymous function often used as an inline function.

22. Why lambda forms in python do not have statements?

Ans: 

A lambda form in python does not have statements as it is used to make new function objects and then return them at runtime.

23. What is a pass in Python?

Ans: 

Pass means, no-operation Python statement, or in other words, it is a placeholder in a compound statement, where there should be a blank left and nothing has to be written there.

24. In Python what are iterators?

Ans: 

In Python, iterators are used to iterate a group of elements, containers like a list.

25. What is the unittest in Python?

Ans: 

A unit testing framework in Python is known as unittest. It supports the sharing of setups, automation testing, shutdown code for tests, aggregation of tests into collections, etc.

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