Elena Kosourova
Elena is a petroleum geologist and community manager at Dataquest. You can find her chatting online with data enthusiasts and writing tutorials on data science topics. Find her on LinkedIn.
21 articles
Elena Kosourova
Elena is a petroleum geologist and community manager at Dataquest. You can find her chatting online with data enthusiasts and writing tutorials on data science topics. Find her on LinkedIn.
21 articles
- Article
How to Append Rows to a Dataframe in R (with 7 Code Examples)
In this tutorial, we'll cover how to append to a DataFrame in R — one of the most common modifications performed on a DataFrame.
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How to Add a Column to a Dataframe in R (with 18 Code Examples)
In this tutorial, you'll learn one of most common operations used for manipulating DataFrames in R — adding columns.
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The Easy Way to Install a Package in R (with 8 Code Examples)
R is a powerful programming language with many data science applications. In this tutorial, we go over how to install packages in R.
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How to Create a Dataframe in R (with 30 Code Examples)
Dataframes are essential data structures in the R programming language. In this tutorial, we'll discuss how to create a dataframe in R.
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25 Must-Know Power BI Interview Questions and Answers
Here are the top 25 questions typically asked during a Power BI job interview — and more importantly, how to answer them!
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20 Business Analyst Interview Questions and Answers
Top 20 data and business analyst interview questions with answers to help you prepare, showcase your skills, and land the job.
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Business Analyst vs. Data Analyst: Which One is Right for You?
Business analysts and data analysts have a lot in common, but there are some key differences. Here's what you need to know.
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How to Write Functions in R (with 18 Code Examples)
Functions are essential tools in R. Here’s what you need to know about creating and calling them — and more.
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How to Use a For-Loop in R (with 18 Code Examples)
A for-loop is one of the main control-flow constructs of the R programming language, used to iterate over a collection of objects.
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How to Install PIP on Windows (w/ Screenshots)
PIP is a package-management system designed to install libraries. This tutorial covers how to install PIP for Python on Windows.
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Python Exceptions: The Ultimate Beginner's Guide (with Examples)
This tutorial covers exceptions in Python, including why they occur, how to identify them, and how to resolve them.
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Apply Functions in R with Examples [apply(), sapply(), lapply (), tapply()]
In this tutorial, we'll learn about the apply() function in R, including when to use it and why it's more efficient than loops.
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Tutorial: Lambda Functions in Python
In this tutorial, we will define lambda functions in Python and explore the advantages and limitations of employing them.
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Tutorial: Reset Index in Pandas
In this tutorial, we'll explain the reset_index() pandas method, including how and when to use it — and more.
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Tutorial: Indexing DataFrames in Pandas
A complete guide to indexing DataFrames in pandas. We use examples to answer questions like: What is pandas dataframe indexing? Why do we need it? And more!
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Grouping Data: A Step-by-Step Tutorial to GroupBy in Pandas
Are you working with data in Python? Here’s a step-by-step tutorial to working with GroupBy in Pandas! We explore each step of the grouping process and more.
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Python Classes and Objects: A Beginner's Guide (2026)
Learn Python classes with clear examples. Understand constructors, instance variables, inheritance, and OOP basics. Perfect guide for beginners.
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Tutorial: Everything You Need to Know About Python Sets
This tutorial explains everything you need to know about Python sets! With examples, this guide teaches you how to create, modify, and use sets in Python.
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Tutorial: Installing Python on Windows
A tutorial on how to install and run Python on Windows. Everything from downloading it on the official website or Anaconda, to updating it and running scripts.
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8 Rarely Used Python Libraries & How to Use Them
Discover how to use eight handy but rarely used Python libraries to give you an edge on your next project. This guide includes over a dozen real-world examples.
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How to Plot a Bar Graph in Matplotlib: The Easy Way
Unlock powerful visualization features of your bar plots by making your data more informative and efficient—shown with 9 in-depth examples.
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