Suppose I have a CSV file called data.csv saved in the following location:
C:UsersBobDesktopdata.csv
And suppose the CSV file contains the following data:
team, points, assists 'A', 78, 12 'B', 85, 20 'C', 93, 23 'D', 90, 8 'E', 91, 14
There are three common ways to import this CSV file into R:
1. Use read.csv from base R (Slowest method, but works fine for smaller datasets)
data1 C:\Users\Bob\Desktop\data.csv", header=TRUE, stringsAsFactors=FALSE)
2. Use read_csv from readr package (2-3x faster than read.csv)
library(readr)
data2 C:\Users\Bob\Desktop\data.csv")
3. Use fread from data.table package (2-3x faster than read_csv)
library(data.table)
data3 C:\Users\Bob\Desktop\data.csv")
This tutorial shows an example of how to use each of these methods to import the CSV file into R.
Method 1: Using read.csv
If your CSV file is reasonably small, you can just use the read.csv function from Base R to import it.
When using this method, be sure to specify stringsAsFactors=FALSE so that R doesn’t convert character or categorical variables into factors.
The following code shows how to use read.csv to import this CSV file into R:
#import data data1 C:\Users\Bob\Desktop\data.csv", header=TRUE, stringsAsFactors=FALSE) #view structure of data str(data1) 'data.frame': 5 obs. of 3 variables: $ team : chr "'A'" "'B'" "'C'" "'D'" ... $ points : int 78 85 93 90 91 $ assists: int 12 20 23 8 14
Method 2: Using read_csv
If you’re working with larger files, you can use the read_csv function from the readr package:
library(readr) #import data data2 C:\Users\Bob\Desktop\data.csv") #view structure of data str(data2) 'data.frame': 5 obs. of 3 variables: $ team : chr "'A'" "'B'" "'C'" "'D'" ... $ points : int 78 85 93 90 91 $ assists: int 12 20 23 8 14
Method 3: Using fread
If your CSV is extremely large, the fastest way to import it into R is with the fread function from the data.table package:
library(data.table) #import data data3 C:\Users\Bob\Desktop\data.csv") #view structure of data str(data3) Classes 'data.table' and 'data.frame': 5 obs. of 3 variables: $ team : chr "'A'" "'B'" "'C'" "'D'" ... $ points : int 78 85 93 90 91 $ assists: int 12 20 23 8 14
Note that in each example we used double backslashes (\) in the file path to avoid the following common error:
Error: 'U' used without hex digits in character string starting ""C:U"
Additional Resources
The following tutorials explain how to import other file types into R:
How to Import Excel Files into R
How to Import TSV Files into R
How to Import Zip Files into R
How to Import SAS Files into R
How to Import .dta Files into R