data.table: fread

Introduction to Importing Data in R

Filip Schouwenaars

Instructor, DataCamp

data.table

Matt Dowle & Arun Srinivasan
Key metric: speed
Data manipulation in R
Function to import data: fread()

install.packages("data.table")
library(data.table)

Similar to read.table()

fread()

states.csv

state,capital,pop_mill,area_sqm
South Dakota,Pierre,0.853,77116
New York,Albany,19.746,54555
Oregon,Salem,3.970,98381
Vermont,Montpelier,0.627,9616
Hawaii,Honolulu,1.420,10931

states2.csv

South Dakota,Pierre,0.853,77116
New York,Albany,19.746,54555
Oregon,Salem,3.970,98381
Vermont,Montpelier,0.627,9616
Hawaii,Honolulu,1.420,10931

fread()

fread("states.csv")

          state    capital pop_mill area_sqm
1: South Dakota     Pierre    0.853    77116
2:     New York     Albany   19.746    54555
3:       Oregon      Salem    3.970    98381
4:      Vermont Montpelier    0.627     9616
5:       Hawaii   Honolulu    1.420    10931

fread("states2.csv")

             V1         V2     V3    V4
1: South Dakota     Pierre  0.853 77116
2:     New York     Albany 19.746 54555
3:       Oregon      Salem  3.970 98381
4:      Vermont Montpelier  0.627  9616
5:       Hawaii   Honolulu  1.420 10931

fread()

Infer column types and separators
It simply works
Extremely fast
Possible to specify numerous parameters
Improved read.table()
Fast, convenient, customizable

Let's practice!

Introduction to Importing Data in R