data.table：fread

R 資料匯入入門

Filip Schouwenaars

Instructor, DataCamp

data.table

Matt Dowle 與 Arun Srinivasan
核心指標：速度
在 R 進行資料處理
匯入資料的函式：fread()

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

類似 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()

自動推斷欄位型別與分隔符
開箱即用
極快
可設定多種參數
加強版 read.table()
快速、便利、可自訂

一起來練習吧！

R 資料匯入入門