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Course

Joining Data with data.table in R

Intermediate

5

Updated 05/2025

This course will show you how to combine and merge datasets with data.table.

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RData Manipulation4 hours13 videos47 Exercises3,950 XP16,677Statement of Accomplishment

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Course Description

In the real world, data sets typically come split across many tables while most data analysis functions in R are designed to work with single tables of data. In this course, you'll learn how to effectively combine data sets into single tables using data.table. You'll learn how to add columns from one table to another table, how to filter a table based on observations in another table, and how to identify records across multiple tables matching complex criteria. Along the way, you'll learn how to troubleshoot failed join operations and best practices for working with complex data sets. After completing this course you'll be well on your way to be a data.table master!

Prerequisites

Data Manipulation with data.table in R

1

Joining Multiple data.tables

Welcome to the course

Exploring data.tables

Identifying join keys

Multiple data.tables, multiple keys

The merge function

Left and right joins

Mastering simple joins

2

Joins Using data.table Syntax

Joins using data.table syntax

Right join with the data.table syntax

Inner join with the data.table syntax

Setting and viewing data.table keys

Setting keys

Getting keys

Incorporating joins into your data.table workflow

Exploring the Australian population

Finding multiple matches

Exploring world life expectancy

3

Diagnosing and Fixing Common Join Problems

Complex keys

Keys with different names

Multi-column keys

Multi-key, single-key

Tricky columns

Column name suffixes

Joining a data.frame

Duplicate matches

Joining with missing values

Filtering duplicates

Joining and filtering duplicates

4

Concatenating and Reshaping data.tables

Concatenating two or more data.tables

Concatenating data.table variables

Concatenating a list of data.tables

Set operations

Identifying observations shared by multiple tables

Removing duplicates while combining tables

Identifying observations unique to a table

Melting data.tables

Melting a wide table

Casting data.tables

Casting a long table

Casting multiple columns

Splitting by multiple groups

Joining Data with data.table in R

Course
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Most recent
Top reviews

Fuuk

7 days

Lots of new stuff to learn. Very compact. Well thought-out!

Derek

10 days

Annabelle

16 days

Ricardo

30 days

This course was very informative but also very difficult to follow. Please consider to split into two different courses and make the learning pace better

Prashansa Mahesh

about 1 month

Rachel

about 1 month

This chapter teaches a lot of procedures that programmers typically encounter.

"Lots of new stuff to learn. Very compact. Well thought-out!"

Fuuk

Derek

Annabelle

FAQs

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