$:リスト要素にアクセスする。
[]:ベクトル要素にアクセスする。
[[]]:リスト要素にアクセスする。
mpg <- mtcars$mpgmtcars[1]## mpg
## Mazda RX4 21.0
## Mazda RX4 Wag 21.0
## Datsun 710 22.8
## Hornet 4 Drive 21.4
## Hornet Sportabout 18.7
## Valiant 18.1
## Duster 360 14.3
## Merc 240D 24.4
## Merc 230 22.8
## Merc 280 19.2
## Merc 280C 17.8
## Merc 450SE 16.4
## Merc 450SL 17.3
## Merc 450SLC 15.2
## Cadillac Fleetwood 10.4
## Lincoln Continental 10.4
## Chrysler Imperial 14.7
## Fiat 128 32.4
## Honda Civic 30.4
## Toyota Corolla 33.9
## Toyota Corona 21.5
## Dodge Challenger 15.5
## AMC Javelin 15.2
## Camaro Z28 13.3
## Pontiac Firebird 19.2
## Fiat X1-9 27.3
## Porsche 914-2 26.0
## Lotus Europa 30.4
## Ford Pantera L 15.8
## Ferrari Dino 19.7
## Maserati Bora 15.0
## Volvo 142E 21.4mtcars[c(2,4)]## cyl hp
## Mazda RX4 6 110
## Mazda RX4 Wag 6 110
## Datsun 710 4 93
## Hornet 4 Drive 6 110
## Hornet Sportabout 8 175
## Valiant 6 105
## Duster 360 8 245
## Merc 240D 4 62
## Merc 230 4 95
## Merc 280 6 123
## Merc 280C 6 123
## Merc 450SE 8 180
## Merc 450SL 8 180
## Merc 450SLC 8 180
## Cadillac Fleetwood 8 205
## Lincoln Continental 8 215
## Chrysler Imperial 8 230
## Fiat 128 4 66
## Honda Civic 4 52
## Toyota Corolla 4 65
## Toyota Corona 4 97
## Dodge Challenger 8 150
## AMC Javelin 8 150
## Camaro Z28 8 245
## Pontiac Firebird 8 175
## Fiat X1-9 4 66
## Porsche 914-2 4 91
## Lotus Europa 4 113
## Ford Pantera L 8 264
## Ferrari Dino 6 175
## Maserati Bora 8 335
## Volvo 142E 4 109#mtcars[,c(2,4)]
mtcars[,c(2:4)]## cyl disp hp
## Mazda RX4 6 160.0 110
## Mazda RX4 Wag 6 160.0 110
## Datsun 710 4 108.0 93
## Hornet 4 Drive 6 258.0 110
## Hornet Sportabout 8 360.0 175
## Valiant 6 225.0 105
## Duster 360 8 360.0 245
## Merc 240D 4 146.7 62
## Merc 230 4 140.8 95
## Merc 280 6 167.6 123
## Merc 280C 6 167.6 123
## Merc 450SE 8 275.8 180
## Merc 450SL 8 275.8 180
## Merc 450SLC 8 275.8 180
## Cadillac Fleetwood 8 472.0 205
## Lincoln Continental 8 460.0 215
## Chrysler Imperial 8 440.0 230
## Fiat 128 4 78.7 66
## Honda Civic 4 75.7 52
## Toyota Corolla 4 71.1 65
## Toyota Corona 4 120.1 97
## Dodge Challenger 8 318.0 150
## AMC Javelin 8 304.0 150
## Camaro Z28 8 350.0 245
## Pontiac Firebird 8 400.0 175
## Fiat X1-9 4 79.0 66
## Porsche 914-2 4 120.3 91
## Lotus Europa 4 95.1 113
## Ford Pantera L 8 351.0 264
## Ferrari Dino 6 145.0 175
## Maserati Bora 8 301.0 335
## Volvo 142E 4 121.0 109mtcars[0]## 0 列 32 行のデータフレームmtcars[-c(2:11)]## mpg
## Mazda RX4 21.0
## Mazda RX4 Wag 21.0
## Datsun 710 22.8
## Hornet 4 Drive 21.4
## Hornet Sportabout 18.7
## Valiant 18.1
## Duster 360 14.3
## Merc 240D 24.4
## Merc 230 22.8
## Merc 280 19.2
## Merc 280C 17.8
## Merc 450SE 16.4
## Merc 450SL 17.3
## Merc 450SLC 15.2
## Cadillac Fleetwood 10.4
## Lincoln Continental 10.4
## Chrysler Imperial 14.7
## Fiat 128 32.4
## Honda Civic 30.4
## Toyota Corolla 33.9
## Toyota Corona 21.5
## Dodge Challenger 15.5
## AMC Javelin 15.2
## Camaro Z28 13.3
## Pontiac Firebird 19.2
## Fiat X1-9 27.3
## Porsche 914-2 26.0
## Lotus Europa 30.4
## Ford Pantera L 15.8
## Ferrari Dino 19.7
## Maserati Bora 15.0
## Volvo 142E 21.4mtcars["cyl"]## cyl
## Mazda RX4 6
## Mazda RX4 Wag 6
## Datsun 710 4
## Hornet 4 Drive 6
## Hornet Sportabout 8
## Valiant 6
## Duster 360 8
## Merc 240D 4
## Merc 230 4
## Merc 280 6
## Merc 280C 6
## Merc 450SE 8
## Merc 450SL 8
## Merc 450SLC 8
## Cadillac Fleetwood 8
## Lincoln Continental 8
## Chrysler Imperial 8
## Fiat 128 4
## Honda Civic 4
## Toyota Corolla 4
## Toyota Corona 4
## Dodge Challenger 8
## AMC Javelin 8
## Camaro Z28 8
## Pontiac Firebird 8
## Fiat X1-9 4
## Porsche 914-2 4
## Lotus Europa 4
## Ford Pantera L 8
## Ferrari Dino 6
## Maserati Bora 8
## Volvo 142E 4# 1番目の列
mtcars[[1]]## [1] 21.0 21.0 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 17.8 16.4 17.3 15.2
## [15] 10.4 10.4 14.7 32.4 30.4 33.9 21.5 15.5 15.2 13.3 19.2 27.3 26.0 30.4
## [29] 15.8 19.7 15.0 21.4# 'cyl'の列
mtcars[["cyl"]]## [1] 6 6 4 6 8 6 8 4 4 6 6 8 8 8 8 8 8 4 4 4 4 8 8 8 8 4 4 4 8 6 8 4# 'Datson 170'の'wt'にアクセス
mtcars[[2,"wt"]]## [1] 2.875head:データの先頭行をn行抽出する。
tail:データの最終行からn行抽出する。
head(mtcars,3)## mpg cyl disp hp drat wt qsec vs am gear carb
## Mazda RX4 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4
## Mazda RX4 Wag 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4
## Datsun 710 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1tail(mtcars,5)## mpg cyl disp hp drat wt qsec vs am gear carb
## Lotus Europa 30.4 4 95.1 113 3.77 1.513 16.9 1 1 5 2
## Ford Pantera L 15.8 8 351.0 264 4.22 3.170 14.5 0 1 5 4
## Ferrari Dino 19.7 6 145.0 175 3.62 2.770 15.5 0 1 5 6
## Maserati Bora 15.0 8 301.0 335 3.54 3.570 14.6 0 1 5 8
## Volvo 142E 21.4 4 121.0 109 4.11 2.780 18.6 1 1 4 2データを条件で検索する。
subset(mtcars,cyl <= 4)## mpg cyl disp hp drat wt qsec vs am gear carb
## Datsun 710 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1
## 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
## Fiat 128 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 1
## Honda Civic 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 2
## Toyota Corolla 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1
## Toyota Corona 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 1
## Fiat X1-9 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 1
## Porsche 914-2 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 2
## Lotus Europa 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2
## Volvo 142E 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2# am:a=automatic and max(mpg)
subset(mtcars, am == 1 & mpg == max(mpg))## mpg cyl disp hp drat wt qsec vs am gear carb
## Toyota Corolla 33.9 4 71.1 65 4.22 1.835 19.9 1 1 4 1複数条件では、& (AND条件), | (OR条件)を使う。
データフレームで列にアクセスする場合、列名を省略できる関数。
# 燃費(mpg)のZ値を求める
z <- (mtcars$mpg - mean(mtcars$mpg)) / sd(mtcars$mpg)
z## [1] 0.15088482 0.15088482 0.44954345 0.21725341 -0.23073453
## [6] -0.33028740 -0.96078893 0.71501778 0.44954345 -0.14777380
## [11] -0.38006384 -0.61235388 -0.46302456 -0.81145962 -1.60788262
## [16] -1.60788262 -0.89442035 2.04238943 1.71054652 2.29127162
## [21] 0.23384555 -0.76168319 -0.81145962 -1.12671039 -0.14777380
## [26] 1.19619000 0.98049211 1.71054652 -0.71190675 -0.06481307
## [31] -0.84464392 0.21725341z1 <- with(mtcars, (mpg - mean(mpg)) / sd(mpg))
z1## [1] 0.15088482 0.15088482 0.44954345 0.21725341 -0.23073453
## [6] -0.33028740 -0.96078893 0.71501778 0.44954345 -0.14777380
## [11] -0.38006384 -0.61235388 -0.46302456 -0.81145962 -1.60788262
## [16] -1.60788262 -0.89442035 2.04238943 1.71054652 2.29127162
## [21] 0.23384555 -0.76168319 -0.81145962 -1.12671039 -0.14777380
## [26] 1.19619000 0.98049211 1.71054652 -0.71190675 -0.06481307
## [31] -0.84464392 0.21725341名前xに、オブジェクト値Valueを割り当てる。
# 'file3'に33を割り当てる
assign(paste("file", 3, sep=""), 33)
file3## [1] 33オブジェクトの名前を指定すると、そのオブジェクトを取得する。
m <- mtcars
get("m")## 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
## Merc 280 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 4
## Merc 280C 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 4
## Merc 450SE 16.4 8 275.8 180 3.07 4.070 17.40 0 0 3 3
## Merc 450SL 17.3 8 275.8 180 3.07 3.730 17.60 0 0 3 3
## Merc 450SLC 15.2 8 275.8 180 3.07 3.780 18.00 0 0 3 3
## Cadillac Fleetwood 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 4
## Lincoln Continental 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 4
## Chrysler Imperial 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 4
## Fiat 128 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 1
## Honda Civic 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 2
## Toyota Corolla 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1
## Toyota Corona 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 1
## Dodge Challenger 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 2
## AMC Javelin 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 2
## Camaro Z28 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 4
## Pontiac Firebird 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 2
## Fiat X1-9 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 1
## Porsche 914-2 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 2
## Lotus Europa 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2
## Ford Pantera L 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 4
## Ferrari Dino 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 6
## Maserati Bora 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 8
## Volvo 142E 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2copyrigth © 2016 r-beginners.com All rigths reserved.
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