data()
data(trees)
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 <- c('C','H','V')
head(d)
##   Girth Height Volume
## 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   19.7
Vol <- d$V
Vol
##  [1] 10.3 10.3 10.2 16.4 18.8 19.7 15.6 18.2 22.6 19.9 24.2 21.0 21.4 21.3 19.1
## [16] 22.2 33.8 27.4 25.7 24.9 34.5 31.7 36.3 38.3 42.6 55.4 55.7 58.3 51.5 51.0
## [31] 77.0
Vol15 <- Vol[Vol>15 & Vol<50]
Vol15
##  [1] 16.4 18.8 19.7 15.6 18.2 22.6 19.9 24.2 21.0 21.4 21.3 19.1 22.2 33.8 27.4
## [16] 25.7 24.9 34.5 31.7 36.3 38.3 42.6
table(cut(Vol,4))
## 
## (10.1,26.9] (26.9,43.6] (43.6,60.3] (60.3,77.1] 
##          18           7           5           1
data("iris")
cut(iris$Petal.Length,4)
##   [1] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48]
##   [6] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48]
##  [11] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48]
##  [16] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48]
##  [21] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48]
##  [26] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48]
##  [31] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48]
##  [36] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48]
##  [41] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48]
##  [46] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48] (0.994,2.48]
##  [51] (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (3.95,5.43] 
##  [56] (3.95,5.43]  (3.95,5.43]  (2.48,3.95]  (3.95,5.43]  (2.48,3.95] 
##  [61] (2.48,3.95]  (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (2.48,3.95] 
##  [66] (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (2.48,3.95] 
##  [71] (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (3.95,5.43] 
##  [76] (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (2.48,3.95] 
##  [81] (2.48,3.95]  (2.48,3.95]  (2.48,3.95]  (3.95,5.43]  (3.95,5.43] 
##  [86] (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (3.95,5.43] 
##  [91] (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (2.48,3.95]  (3.95,5.43] 
##  [96] (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (2.48,3.95]  (3.95,5.43] 
## [101] (5.43,6.91]  (3.95,5.43]  (5.43,6.91]  (5.43,6.91]  (5.43,6.91] 
## [106] (5.43,6.91]  (3.95,5.43]  (5.43,6.91]  (5.43,6.91]  (5.43,6.91] 
## [111] (3.95,5.43]  (3.95,5.43]  (5.43,6.91]  (3.95,5.43]  (3.95,5.43] 
## [116] (3.95,5.43]  (5.43,6.91]  (5.43,6.91]  (5.43,6.91]  (3.95,5.43] 
## [121] (5.43,6.91]  (3.95,5.43]  (5.43,6.91]  (3.95,5.43]  (5.43,6.91] 
## [126] (5.43,6.91]  (3.95,5.43]  (3.95,5.43]  (5.43,6.91]  (5.43,6.91] 
## [131] (5.43,6.91]  (5.43,6.91]  (5.43,6.91]  (3.95,5.43]  (5.43,6.91] 
## [136] (5.43,6.91]  (5.43,6.91]  (5.43,6.91]  (3.95,5.43]  (3.95,5.43] 
## [141] (5.43,6.91]  (3.95,5.43]  (3.95,5.43]  (5.43,6.91]  (5.43,6.91] 
## [146] (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (3.95,5.43]  (3.95,5.43] 
## Levels: (0.994,2.48] (2.48,3.95] (3.95,5.43] (5.43,6.91]
table(cut(iris$Petal.Length,4))
## 
## (0.994,2.48]  (2.48,3.95]  (3.95,5.43]  (5.43,6.91] 
##           50           11           61           28
table(cut(iris$Petal.Length,4),iris$Species)
##               
##                setosa versicolor virginica
##   (0.994,2.48]     50          0         0
##   (2.48,3.95]       0         11         0
##   (3.95,5.43]       0         39        22
##   (5.43,6.91]       0          0        28