Python Machine Learning Deep Learning Data Structure


Here are the most common and often asked Python Programming Language questions during job interviews or internships. Each question's answer is written in simple language, so you should be able to understand it all.

1. What is Python?

Python is a very popular programming language created by Guido van Rossum and released in 1991. It is platform independent, high-level, object-oriented language. Python requires less code as compared to other programming languages in solving the same problems. It is widely used in machine learning, deep learning, data science, and artificial intelligence domain. This programming language has a very simple syntax.

2. Where can you use Python programming language or what are the applications of Python programming language?

We can use Python programming language in many areas:

  • GUI-based desktop applications
  • Web and Internet Development
  • Games
  • Image processing and object detection
  • Solve complex problems

3. What are the various web frameworks to develop web applications?

Python provides various web frameworks to develop web apps. The popular frameworks are Flask and Django.

4. What are the key features of Python?

  • Python is Free and open source. It is available for free download.
  • Python is an interpreted language. That means Python executes its statements line by line. The program does not need to be compiled before it is run. Languages such as Python, JavaScript, and PHP are examples of interpreted languages.
  • Python is dynamically typed. That means we don't need to state the types of variables (int, string, float) when we declare them.
  • Python is also an Object-oriented programming that includes some properties of OOP like it allows the definition of classes and supports inheritance mechanism. But it doesn't include access specifiers like public or private.
  • Python has built-in data structures like Tuples, List, and Dictionary.
  • Python is Portable. That means Python programs can run on cross-platforms without affecting their performance.

5. What is PEP 8 in Python?

PEP stands for Python Enhancement Proposal. It is a report that contains principles and best practices for writing Python code. It helps to improve the readability of Python code.

6. What are lists and tuples? What is the key difference between the two?

Lists and Tuples are used to store one or more Python objects or data-type sequentially. List is just like an array which is used to store multiple data at the same time.

Syntax: lst = ['Python', 4, 'Java', 'Ram']
Tuple is also a sequence data type, just like a list but these are immutable in nature. That means tuple data are unable to change over time.

Syntax: tpl = ('Python', 4, 'Java', 'Ram')
Note: We use a square bracket to represent a list whereas, we use parenthesis to represent a tuple.


Note: we get an error because a tuple is immutable. We can't change the data value over time.

7. What is a dictionary in Python?

A dictionary is an unordered collection of items that are used to store data values in key:value pairs. The keys are unique whereas the values can be duplicates.



8. What is set? How set differ from a list?

A set is an unordered collection of data types that is iterable, mutable, and contains unique elements.

We use parenthesis to represent a set just like a dictionary. The difference is that dictionary has key:value pair whereas a set has only keys.



A list may contain duplicate elements whereas a set does not.



9. What is a function in Python?

A function is a chunk of code that only executes when called. Once we create a function, we can use that function from anywhere inside a program. In Python, a function is defined using def keyword and to call a function, we can use the same function name. Two terms parameters and arguments are most common in function. 

  • A parameter is a variable in the function definition that is listed between parentheses.
  • When a function is called, its arguments are passed to it.


10. What are the typical Python built-in data types?

Python's standard built-in data types are:

  • Numbers
  • String
  • Boolean
  • List
  • Tuple
  • Dictionary
  • Set

11. What is the use of a split() method in Python?

A split() method is used to divide a string into a list. We can pass a separator inside a parameter as below:



11. What is the use of a join() method in Python?

The join() method unites all items in an iterable (list, string, or tuple) into a string.

Example: We use a join() method to convert a list to a string as below:



13. How can whitespace be removed from a string in Python?

To remove leading and trailing whitespaces from a string, we can use a strip() method.

And to remove the whitespace between the string, we can use a split() and join() method.



14. What is the use of break, continue and pass statements in Python?

All break, continue and pass statement is used to alter the normal flow of la oop. 

  • The break statement allows us to exit a loop when a particular condition is met. It returns the control outside the loop.
  • The continue statement allows us to skip part of a loop when a particular condition is met. It returns the control to the beginning of the loop.
  • A pass statement is a null operation. Nothing will happen when it executes. We write pass inside function or loop which indicates that the code will be placed later but has not been written yet.



15. What is a local and global variable in Python?

Local variables are variables that are declared inside a function and its scope is limited within that function only whereas global variables are declared outside a function and can be accessible throughout the program inside and outside of every function. 

We use the global keyword inside the function to make that variable to be accessible from anywhere.




16. What is slicing in Python?

Slicing means taking a range of items from one given index to another index.

Syntax:

list[start_index : end_index]

list[start_index : end_index : step_argument]

  • In the first syntax, step_argument is 1 by default.
  • Slicing will slice from the start index to end_index -1. For example in lst[2:8], it will slice from 2 to 8-1=7.


In a tuple, we have a slice() method to do the same job.


17. How do you create a class in Python?

A class is a blueprint for creating objects. We can create a class using the keyword "class".

Syntax:

class class_name


18. What is self in Python?

Self represents an instance of a class. By using the self keyword, we can access the attributes and methods of a class. In simple terms, self refers to a current object. 



19 . What is __init__ in python?

or

  What is a constructor in Python?

__init__ is a reserved method in Python classes. It is similar to the constructor. When an object is created, this method is invoked.

Constructors are used to initialize or assign value to the data member of the class when an object of a class is created.

20. How to create the object of class?

An object is simply a collection of data (variables) and methods (function). To create the object of a class, we can use the same class name for which the object of the class is created.



  • While creating an object, we have to pass two parameters because our __init__ function takes two parameters i.e., name and age.
  • If we have __init__function like def __init__(self), we don't need to pass any parameter. All we have to do is create an object like obj = class_name().

21. What is inheritance in Python? How can we achieve this?

Inheritance allows us to construct a class that inherits all methods and attributes from another class.

In other words, the inheritance method allows a child or derived class to inherit all methods and properties from the parent or base class.

Syntax:

Class parent_class_name:    // methods and attributes

Class derived_class_name(parent_class_name):    // other additional methods and attributes




22. What is list and dictionary comprehension?

Comprehension provides a short and concise (brief but comprehensive) way to create a new sequence using a previously defined sequence. They are generally one-line codes.

List comprehension provides a concise way to create a list. 





Dictionary comprehension provides a concise way to create a dictionary.



Like list and dictionary comprehension, we also have set comprehension: