4  Intro

What is ETL about ? Why do we need it ?

ETL stands for Extract Transform Load.

It’s also called data wrangling or data processing (there are much more similar descriptions).

Basically, it’s about :

• taking some raw data, which might not be yet in the format that we want.

• performing some operations, such as :

  • data cleansing

  • aggregations (think about a pivot table in Excel)

  • mergers with other datasets (like a VLOOKUP in Excel, but with more capabilities)

  • calculations (here, things are getting pretty fun)

With R it is relatively easy to perform some complex calculations (vs Excel or classic BI tools).

This chapter is divided into 4 parts:

1. learn how to use the RStudio or positron IDE, create some quarto document to code, and install some first packages.

2. discover the R environment : data structures, and some basic features, like uploading and writing data.

3. manipulate data frames. We will learn several key functions to use in our work.

4. practice on some simple exercises

remember “there is always more than one way to realize one action in R”

Through practicing and writing your own code you will find the syntax which best suits:

• your style (logic / problem solving approach)

• or the problem you want to solve (faster, easier script)