A discussion on the most frequently asked python interview questions for data science

Python has been around for almost four decades now. And during this long existence, the language has become a popular one in a plethora of fields. Python is easy to learn. And, even the technologically challenged can master it with the right guidance and practice. The syntax of python is easy and can be understood with ease. Furthermore, Python is free. It comes pre-installed with Linux and can be installed on windows in a couple of minutes. 

The language comes with libraries of prewritten codes, and there’s an abundance of libraries that are aligned with data science interests. The python community, thanks to its long existence, consists of a variety of age groups. People from all levels of skill and experience. Thus getting the necessary guidance is never a challenge for budding data scientists. Data science, being a liberal discipline, welcomes brilliant minds from a plethora of backgrounds. Thus, Python is preferred for its versatility and ease of use. And the knowledge of python matters for data scientists of all stature. 

This article will thus concentrate on discussing the most popular python interview questions for data science. And add to the interview preparation of a budding data scientist, almost ready to embark on a job search. 

What is a dynamically typed language?

Typing refers to type checking in programming languages. And based on the approach of implicit conversion of data types, languages can be classified into two major groups. Strongly typed languages and weakly typed languages. For instance, in the case of a strongly typed language like python, 1+2 will not be recognized as valid and will result in a type error. But a weakly typed language like javascript 1+2 will result in an output of 12. 

In python, type checking is a real-time ( dynamic ) process and the programs are executed in a line-by-line approach. Thus, Python is a dynamically typed language. 

Explain scopes in python 

A scope is a space, a block of code, where an object in python remains relevant. Every object in python functions within a scope. 

  • Local objects that are available in a function are called local scope.
  • Global scope is concerned with all the objects that are functioning throughout the code. 
  • Objects functional in the current module of a code are called module-level scope.

What are the three main attributes of python?


Public variables, that are functional in a global scope are called global variables


Attributes that are defined by an underscore prefix to their identifier are termed protected attributes.


An object that can not be accessed from the outside is prefixed with a double underscore. And they are termed as protected attributes. 

What are unit tests?

In python software is developed in units, simply understood as components of the software. (eg. a digital audio interface has different components for mixing, tracking, and adding effects.) While checking the fitness of the software, each component is tested separately. Thus, problems in one of the components can be detected in an isolated manner. Instead of looking up the whole code for a single error. 

What is slicing in python?

Slicing in python, as the name suggests separation based on a step value.  The syntax for slicing =      [ start : stop : step ]

  • The start in this syntax is the starting point 
  • The stop is an ending index where the process will stop 
  • The step is the number of steps to jump 

The process can be applied to strings, arrays, lists, and tuples.

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

print(numbers[1 : : 2])  #output : [2, 4, 6, 8, 10]

How memory is managed in python 

There is a dedicated python memory manager in python. The memory allocated to python by the manager is found in the form of private heap space. All objects relevant to python are stored in this heap. And being private this heap is largely inaccessible to the programmer. Furthermore, the inbuilt garbage recycler of python can recycle the unused memory for the heap. 

Write a code for deleting a file in python?

Use command os.remove(file_name)

import os


print(“File Removed!”)