Reading Data into R

Interactive beginner R tutorial on importing data: the working directory, read.csv() and write.csv(), inspecting with str() and head(), and a note on readr. Run real R in your browser.

Sooner or later you stop using built-in datasets and load your own. This is how. Everything below is a live R console — edit the code and press Run Code.

Watch: reading data into R

The working directory, read.csv() and write.csv(), and why you should always inspect a fresh import.

Download the R script · ▶ Practice in the playground — or edit and run each snippet below.

Where does R look for files?

R reads and writes relative to the working directory. getwd() shows it (setwd() changes it):

Write a CSV, then read it back

write.csv() saves a data frame; read.csv() loads one. Here we round-trip mtcars:

Always look after importing

Before analysing, check the structure and the first rows — column types and unexpected text hide here:

Real files and faster reads

For a file on disk you give the path, e.g. read.csv("data/cars.csv"). For big files the readr package’s read_csv() is faster and guesses types better:

Your turn

Next: Writing your own functions → — packaging steps you repeat.