R 基礎介紹

顯示當前所有資料集：

data()

AirPassengers Monthly Airline Passenger Numbers 1949-1960 BJsales Sales Data with Leading Indicator BJsales.lead (BJsales) Sales Data with Leading Indicator BOD Biochemical Oxygen Demand CO2 Carbon Dioxide Uptake in Grass Plants ChickWeight Weight versus age of chicks on different diets DNase Elisa assay of DNase EuStockMarkets Daily Closing Prices of Major European Stock Indices, 1991-1998

顯示資料集：

mtcars

head(mtcars, n=10)

tail(mtcars, n=10)

mpg cyl disp hp drat wt qsec vs am gear carb Mazda RX4 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4 Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4 Datsun 710 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1 Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1 Hornet Sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2 Valiant 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 1 Duster 360 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 4 Merc 240D 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 2 Merc 230 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 2

顯示資料集欄位：

colnames(mtcars)

"mpg" "cyl" "disp" "hp" "drat" "wt" "qsec" "vs" "am" "gear" "carb"

顯示資料集列名稱：

rownames(mtcars)

[1] "Mazda RX4" "Mazda RX4 Wag" "Datsun 710" [4] "Hornet 4 Drive" "Hornet Sportabout" "Valiant" [7] "Duster 360" "Merc 240D" "Merc 230" [10] "Merc 280" "Merc 280C" "Merc 450SE"

敘述型統計：

summary(mtcars$hp)

Min. 1st Qu. Median Mean 3rd Qu. Max. 52.0 96.5 123.0 146.7 180.0 335.0

p <- summary(mtcars$hp)

p["Std.Dev"] <- sd(mtcars$hp)

p

Min. 1st Qu. Median Mean 3rd Qu. Max. Std.Dev 52.0000 96.5000 123.0000 146.7000 180.0000 335.0000 68.5629

欄位相關度分析：

mtcars[, c("hp", "mpg", "wt")]

hp mpg wt hp 1.0000000 -0.7761684 0.6587479 mpg -0.7761684 1.0000000 -0.8676594 wt 0.6587479 -0.8676594 1.0000000

簡易繪圖：

plot(mtcars$hp, mtcars$mpg, main="HP ~ MPG", xlab="MPG", ylab="HP")

擷取部分資料集：

mtcars[mtcars$mpg>25 & mtcars$mpg<30, c("mpg", "hp", "wt")]

mpg hp wt Fiat X1-9 27.3 66 1.935 Porsche 914-2 26.0 91 2.140

移除變數或資料集：

rm(p)

儲存變數或資料集：

save(p, file="R-Intro.rda")

載入已儲存變數或資料集：

p <- load("R-Intro.rda")

簡易繪圖：

library(ggplot2)

qplot(x=mpg, y=hp, data=mtcars, main="HP ~ MPG", xlab="MPG", ylab="HP", colour=mpg, size=mpg)