R入門2

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Rの入門2, 簡単にdata frameを操作する

mtcarsデータセット

特にロードする必要もなく、デフォルトで入っている。

mtcars
                     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    2

%>% パイプを使ってデーターセットのサマリーを調べる。

library(dplyr)
mtcars %>% summary()
      mpg             cyl             disp             hp       
 Min.   :10.40   Min.   :4.000   Min.   : 71.1   Min.   : 52.0  
 1st Qu.:15.43   1st Qu.:4.000   1st Qu.:120.8   1st Qu.: 96.5  
 Median :19.20   Median :6.000   Median :196.3   Median :123.0  
 Mean   :20.09   Mean   :6.188   Mean   :230.7   Mean   :146.7  
 3rd Qu.:22.80   3rd Qu.:8.000   3rd Qu.:326.0   3rd Qu.:180.0  
 Max.   :33.90   Max.   :8.000   Max.   :472.0   Max.   :335.0  
      drat             wt             qsec             vs        
 Min.   :2.760   Min.   :1.513   Min.   :14.50   Min.   :0.0000  
 1st Qu.:3.080   1st Qu.:2.581   1st Qu.:16.89   1st Qu.:0.0000  
 Median :3.695   Median :3.325   Median :17.71   Median :0.0000  
 Mean   :3.597   Mean   :3.217   Mean   :17.85   Mean   :0.4375  
 3rd Qu.:3.920   3rd Qu.:3.610   3rd Qu.:18.90   3rd Qu.:1.0000  
 Max.   :4.930   Max.   :5.424   Max.   :22.90   Max.   :1.0000  
       am              gear            carb      
 Min.   :0.0000   Min.   :3.000   Min.   :1.000  
 1st Qu.:0.0000   1st Qu.:3.000   1st Qu.:2.000  
 Median :0.0000   Median :4.000   Median :2.000  
 Mean   :0.4062   Mean   :3.688   Mean   :2.812  
 3rd Qu.:1.0000   3rd Qu.:4.000   3rd Qu.:4.000  
 Max.   :1.0000   Max.   :5.000   Max.   :8.000  

mtcars data frameの構造を表示

print(str(mtcars))
'data.frame':   32 obs. of  11 variables:
 $ mpg : num  21 21 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 ...
 $ cyl : num  6 6 4 6 8 6 8 4 4 6 ...
 $ disp: num  160 160 108 258 360 ...
 $ hp  : num  110 110 93 110 175 105 245 62 95 123 ...
 $ drat: num  3.9 3.9 3.85 3.08 3.15 2.76 3.21 3.69 3.92 3.92 ...
 $ wt  : num  2.62 2.88 2.32 3.21 3.44 ...
 $ qsec: num  16.5 17 18.6 19.4 17 ...
 $ vs  : num  0 0 1 1 0 1 0 1 1 1 ...
 $ am  : num  1 1 1 0 0 0 0 0 0 0 ...
 $ gear: num  4 4 4 3 3 3 3 4 4 4 ...
 $ carb: num  4 4 1 1 2 1 4 2 2 4 ...
NULL

carbカラムのデータタイプを調べる

print(typeof(mtcars$carb))
[1] "double"

carbカラムにユニークな値

print(unique(mtcars$carb))
[1] 4 1 2 3 6 8

carbカラムに1は7個、2は10個などの情報を出す

print(table(mtcars$carb))
 1  2  3  4  6  8 
 7 10  3 10  1  1 

quantile()関数を使って、mpg列の四分位点を調べる

print(quantile(mtcars$mpg))
    0%    25%    50%    75%   100% 
10.400 15.425 19.200 22.800 33.900 

boxplotで簡単に箱ひげ図を作成することができる。

boxplot(mtcars$mpg)

png

mpg列の分散と標準偏差を求める。

print(var(mtcars$mpg))
print(sd(mtcars$mpg))
[1] 36.3241
[1] 6.026948

選択された各列に対して分散を計算する。

print(mtcars %>% select(mpg, disp) %>%  summarise_all(funs(var)))
      mpg    disp
1 36.3241 15360.8

airqualityデータセット

airquality
OzoneSolar.RWindTempMonthDay
41 190 7.467 5 1
36 118 8.072 5 2
12 149 12.674 5 3
18 313 11.562 5 4
NA NA 14.356 5 5
28 NA 14.966 5 6
23 299 8.665 5 7
19 99 13.859 5 8
8 19 20.161 5 9
NA 194 8.669 5 10
7 NA 6.974 5 11
16 256 9.769 5 12
11 290 9.266 5 13
14 274 10.968 5 14
18 65 13.258 5 15
14 334 11.564 5 16
34 307 12.066 5 17
6 78 18.457 5 18
30 322 11.568 5 19
11 44 9.762 5 20
1 8 9.759 5 21
11 320 16.673 5 22
4 25 9.761 5 23
32 92 12.061 5 24
NA 66 16.657 5 25
NA 266 14.958 5 26
NA NA 8.057 5 27
23 13 12.067 5 28
45 252 14.981 5 29
115 223 5.779 5 30
96 167 6.991 9 1
78 197 5.192 9 2
73 183 2.893 9 3
91 189 4.693 9 4
47 95 7.487 9 5
32 92 15.584 9 6
20 252 10.980 9 7
23 220 10.378 9 8
21 230 10.975 9 9
24 259 9.773 9 10
44 236 14.981 9 11
21 259 15.576 9 12
28 238 6.377 9 13
9 24 10.971 9 14
13 112 11.571 9 15
46 237 6.978 9 16
18 224 13.867 9 17
13 27 10.376 9 18
24 238 10.368 9 19
16 201 8.082 9 20
13 238 12.664 9 21
23 14 9.271 9 22
36 139 10.381 9 23
7 49 10.369 9 24
14 20 16.663 9 25
30 193 6.970 9 26
NA 145 13.277 9 27
14 191 14.375 9 28
18 131 8.076 9 29
20 223 11.568 9 30
print(str(airquality))
'data.frame':   153 obs. of  6 variables:
 $ Ozone  : int  41 36 12 18 NA 28 23 19 8 NA ...
 $ Solar.R: int  190 118 149 313 NA NA 299 99 19 194 ...
 $ Wind   : num  7.4 8 12.6 11.5 14.3 14.9 8.6 13.8 20.1 8.6 ...
 $ Temp   : int  67 72 74 62 56 66 65 59 61 69 ...
 $ Month  : int  5 5 5 5 5 5 5 5 5 5 ...
 $ Day    : int  1 2 3 4 5 6 7 8 9 10 ...
NULL

construct 9 number of equally-spaced bins for us by using the cut function. 間隔は同じで、その間隔に入っている数字の数は違うかも。table関数でみることができる

print(cut(airquality$Temp, 9))
  [1] (65.1,69.7] (69.7,74.2] (69.7,74.2] (60.6,65.1] (56,60.6]   (65.1,69.7]
  [7] (60.6,65.1] (56,60.6]   (60.6,65.1] (65.1,69.7] (69.7,74.2] (65.1,69.7]
 [13] (65.1,69.7] (65.1,69.7] (56,60.6]   (60.6,65.1] (65.1,69.7] (56,60.6]  
 [19] (65.1,69.7] (60.6,65.1] (56,60.6]   (69.7,74.2] (60.6,65.1] (60.6,65.1]
 [25] (56,60.6]   (56,60.6]   (56,60.6]   (65.1,69.7] (78.8,83.3] (78.8,83.3]
 [31] (74.2,78.8] (74.2,78.8] (69.7,74.2] (65.1,69.7] (83.3,87.9] (83.3,87.9]
 [37] (78.8,83.3] (78.8,83.3] (83.3,87.9] (87.9,92.4] (83.3,87.9] (92.4,97]  
 [43] (87.9,92.4] (78.8,83.3] (78.8,83.3] (78.8,83.3] (74.2,78.8] (69.7,74.2]
 [49] (60.6,65.1] (69.7,74.2] (74.2,78.8] (74.2,78.8] (74.2,78.8] (74.2,78.8]
 [55] (74.2,78.8] (74.2,78.8] (74.2,78.8] (69.7,74.2] (78.8,83.3] (74.2,78.8]
 [61] (78.8,83.3] (83.3,87.9] (83.3,87.9] (78.8,83.3] (83.3,87.9] (78.8,83.3]
 [67] (78.8,83.3] (87.9,92.4] (87.9,92.4] (87.9,92.4] (87.9,92.4] (78.8,83.3]
 [73] (69.7,74.2] (78.8,83.3] (87.9,92.4] (78.8,83.3] (78.8,83.3] (78.8,83.3]
 [79] (83.3,87.9] (83.3,87.9] (83.3,87.9] (69.7,74.2] (78.8,83.3] (78.8,83.3]
 [85] (83.3,87.9] (83.3,87.9] (78.8,83.3] (83.3,87.9] (87.9,92.4] (83.3,87.9]
 [91] (78.8,83.3] (78.8,83.3] (78.8,83.3] (78.8,83.3] (78.8,83.3] (83.3,87.9]
 [97] (83.3,87.9] (83.3,87.9] (87.9,92.4] (87.9,92.4] (87.9,92.4] (87.9,92.4]
[103] (83.3,87.9] (83.3,87.9] (78.8,83.3] (78.8,83.3] (78.8,83.3] (74.2,78.8]
[109] (78.8,83.3] (74.2,78.8] (74.2,78.8] (74.2,78.8] (74.2,78.8] (69.7,74.2]
[115] (74.2,78.8] (78.8,83.3] (78.8,83.3] (83.3,87.9] (87.9,92.4] (92.4,97]  
[121] (92.4,97]   (92.4,97]   (92.4,97]   (87.9,92.4] (87.9,92.4] (92.4,97]  
[127] (92.4,97]   (83.3,87.9] (83.3,87.9] (78.8,83.3] (74.2,78.8] (74.2,78.8]
[133] (69.7,74.2] (78.8,83.3] (74.2,78.8] (74.2,78.8] (69.7,74.2] (69.7,74.2]
[139] (74.2,78.8] (65.1,69.7] (74.2,78.8] (65.1,69.7] (78.8,83.3] (60.6,65.1]
[145] (69.7,74.2] (78.8,83.3] (65.1,69.7] (60.6,65.1] (69.7,74.2] (74.2,78.8]
[151] (74.2,78.8] (74.2,78.8] (65.1,69.7]
9 Levels: (56,60.6] (60.6,65.1] (65.1,69.7] (69.7,74.2] ... (92.4,97]
# それぞれの区間内にどれだけ入っているかを調べる
print(table(cut(airquality$Temp, 9)))
  (56,60.6] (60.6,65.1] (65.1,69.7] (69.7,74.2] (74.2,78.8] (78.8,83.3] 
          8          10          14          16          26          35 
(83.3,87.9] (87.9,92.4]   (92.4,97] 
         22          15           7 

carbは1である確率は0.2185, これはPMF(probability mass function)と呼ばれる

print(table(mtcars$carb))
print(table(mtcars$carb) / length(mtcars$carb))
 1  2  3  4  6  8 
 7 10  3 10  1  1 

      1       2       3       4       6       8 
0.21875 0.31250 0.09375 0.31250 0.03125 0.03125 

11と12月のフライトを表示する。 カッコをつけることによって、結果をnov_decに保存して、さらに表示する。

library(nycflights13)
(nov_dec <- filter(flights, month %in% c(11, 12)))

distanceの大きい順でソートする。

arrange(flights, desc(distance))

yearからdayまでの列を除去して、表示する。

select(flights, -(year:day))

destdistance列を先頭に移動して、表示する。

select(flights, dest, distance, everything())

tailnum列名をtail_numに変更する。

rename(flights, tail_num= tailnum)

mutateを使って、新しい変数added_columeを追加する.

mutate(flights, added_colume = distance + 60)

transmuteを使って新しい作った変数added_columeだけを残して表示する。

transmute(flights, added_colume = distance + 60)

About Wang Zhijun
機械学習好きなプログラマー