thao tác trên dataset
data(trees)
str(trees)## 'data.frame': 31 obs. of 3 variables:
## $ Girth : num 8.3 8.6 8.8 10.5 10.7 10.8 11 11 11.1 11.2 ...
## $ Height: num 70 65 63 72 81 83 66 75 80 75 ...
## $ Volume: num 10.3 10.3 10.2 16.4 18.8 19.7 15.6 18.2 22.6 19.9 ...d <- trees
str(d)## 'data.frame': 31 obs. of 3 variables:
## $ Girth : num 8.3 8.6 8.8 10.5 10.7 10.8 11 11 11.1 11.2 ...
## $ Height: num 70 65 63 72 81 83 66 75 80 75 ...
## $ Volume: num 10.3 10.3 10.2 16.4 18.8 19.7 15.6 18.2 22.6 19.9 ...names(d) <- c('c','n','v')head(d)## c n v
## 1 8.3 70 10.3
## 2 8.6 65 10.3
## 3 8.8 63 10.2
## 4 10.5 72 16.4
## 5 10.7 81 18.8
## 6 10.8 83 19.7vol <- d$v
vol15<- vol[vol>15&vol<50]
voll <- d[d$v>15|d$n<60,]
vol15## [1] 16.4 18.8 19.7 15.6 18.2 22.6 19.9 24.2 21.0 21.4 21.3 19.1 22.2 33.8 27.4
## [16] 25.7 24.9 34.5 31.7 36.3 38.3 42.6d$logv <- log(d$v)
d$logn <- log(d$n)
d$Tong <- d$c+d$n+d$c+d$v
cut(vol,4)## [1] (10.1,26.9] (10.1,26.9] (10.1,26.9] (10.1,26.9] (10.1,26.9] (10.1,26.9]
## [7] (10.1,26.9] (10.1,26.9] (10.1,26.9] (10.1,26.9] (10.1,26.9] (10.1,26.9]
## [13] (10.1,26.9] (10.1,26.9] (10.1,26.9] (10.1,26.9] (26.9,43.6] (26.9,43.6]
## [19] (10.1,26.9] (10.1,26.9] (26.9,43.6] (26.9,43.6] (26.9,43.6] (26.9,43.6]
## [25] (26.9,43.6] (43.6,60.3] (43.6,60.3] (43.6,60.3] (43.6,60.3] (43.6,60.3]
## [31] (60.3,77.1]
## Levels: (10.1,26.9] (26.9,43.6] (43.6,60.3] (60.3,77.1]table(cut(vol,4))##
## (10.1,26.9] (26.9,43.6] (43.6,60.3] (60.3,77.1]
## 18 7 5 1rm(d)data('iris')
cut(iris$Sepal.Length,4)## [1] (4.3,5.2] (4.3,5.2] (4.3,5.2] (4.3,5.2] (4.3,5.2] (5.2,6.1] (4.3,5.2]
## [8] (4.3,5.2] (4.3,5.2] (4.3,5.2] (5.2,6.1] (4.3,5.2] (4.3,5.2] (4.3,5.2]
## [15] (5.2,6.1] (5.2,6.1] (5.2,6.1] (4.3,5.2] (5.2,6.1] (4.3,5.2] (5.2,6.1]
## [22] (4.3,5.2] (4.3,5.2] (4.3,5.2] (4.3,5.2] (4.3,5.2] (4.3,5.2] (4.3,5.2]
## [29] (4.3,5.2] (4.3,5.2] (4.3,5.2] (5.2,6.1] (4.3,5.2] (5.2,6.1] (4.3,5.2]
## [36] (4.3,5.2] (5.2,6.1] (4.3,5.2] (4.3,5.2] (4.3,5.2] (4.3,5.2] (4.3,5.2]
## [43] (4.3,5.2] (4.3,5.2] (4.3,5.2] (4.3,5.2] (4.3,5.2] (4.3,5.2] (5.2,6.1]
## [50] (4.3,5.2] (6.1,7] (6.1,7] (6.1,7] (5.2,6.1] (6.1,7] (5.2,6.1]
## [57] (6.1,7] (4.3,5.2] (6.1,7] (4.3,5.2] (4.3,5.2] (5.2,6.1] (5.2,6.1]
## [64] (5.2,6.1] (5.2,6.1] (6.1,7] (5.2,6.1] (5.2,6.1] (6.1,7] (5.2,6.1]
## [71] (5.2,6.1] (5.2,6.1] (6.1,7] (5.2,6.1] (6.1,7] (6.1,7] (6.1,7]
## [78] (6.1,7] (5.2,6.1] (5.2,6.1] (5.2,6.1] (5.2,6.1] (5.2,6.1] (5.2,6.1]
## [85] (5.2,6.1] (5.2,6.1] (6.1,7] (6.1,7] (5.2,6.1] (5.2,6.1] (5.2,6.1]
## [92] (5.2,6.1] (5.2,6.1] (4.3,5.2] (5.2,6.1] (5.2,6.1] (5.2,6.1] (6.1,7]
## [99] (4.3,5.2] (5.2,6.1] (6.1,7] (5.2,6.1] (7,7.9] (6.1,7] (6.1,7]
## [106] (7,7.9] (4.3,5.2] (7,7.9] (6.1,7] (7,7.9] (6.1,7] (6.1,7]
## [113] (6.1,7] (5.2,6.1] (5.2,6.1] (6.1,7] (6.1,7] (7,7.9] (7,7.9]
## [120] (5.2,6.1] (6.1,7] (5.2,6.1] (7,7.9] (6.1,7] (6.1,7] (7,7.9]
## [127] (6.1,7] (5.2,6.1] (6.1,7] (7,7.9] (7,7.9] (7,7.9] (6.1,7]
## [134] (6.1,7] (5.2,6.1] (7,7.9] (6.1,7] (6.1,7] (5.2,6.1] (6.1,7]
## [141] (6.1,7] (6.1,7] (5.2,6.1] (6.1,7] (6.1,7] (6.1,7] (6.1,7]
## [148] (6.1,7] (6.1,7] (5.2,6.1]
## Levels: (4.3,5.2] (5.2,6.1] (6.1,7] (7,7.9]table(cut(iris$Sepal.Length,4),iris$Species)##
## setosa versicolor virginica
## (4.3,5.2] 39 5 1
## (5.2,6.1] 11 29 10
## (6.1,7] 0 16 27
## (7,7.9] 0 0 12