Files corresponding to Short Course: Introduction to Data Science Using R
vec with elements 2, 4, 6, …, 12.vec <- seq(from = 2, to = 12, by = 2)
#or
vec <- (1:6)*2
vec in the
console.vec[c(1, 3, 5)]
## [1] 2 6 10
-’ sign in
front of their indices. Utilize the length() function to see the
vec object in the console without its last element.vec[-length(vec)]
## [1] 2 4 6 8 10
iris dataframe is a built-in R object. Write code to show the
4th column of the iris dataset in the console (there are many ways
to do this!).## using column index
iris[, 4]
## [1] 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 0.2 0.2 0.1 0.1 0.2 0.4 0.4 0.3
## [19] 0.3 0.3 0.2 0.4 0.2 0.5 0.2 0.2 0.4 0.2 0.2 0.2 0.2 0.4 0.1 0.2 0.2 0.2
## [37] 0.2 0.1 0.2 0.2 0.3 0.3 0.2 0.6 0.4 0.3 0.2 0.2 0.2 0.2 1.4 1.5 1.5 1.3
## [55] 1.5 1.3 1.6 1.0 1.3 1.4 1.0 1.5 1.0 1.4 1.3 1.4 1.5 1.0 1.5 1.1 1.8 1.3
## [73] 1.5 1.2 1.3 1.4 1.4 1.7 1.5 1.0 1.1 1.0 1.2 1.6 1.5 1.6 1.5 1.3 1.3 1.3
## [91] 1.2 1.4 1.2 1.0 1.3 1.2 1.3 1.3 1.1 1.3 2.5 1.9 2.1 1.8 2.2 2.1 1.7 1.8
## [109] 1.8 2.5 2.0 1.9 2.1 2.0 2.4 2.3 1.8 2.2 2.3 1.5 2.3 2.0 2.0 1.8 2.1 1.8
## [127] 1.8 1.8 2.1 1.6 1.9 2.0 2.2 1.5 1.4 2.3 2.4 1.8 1.8 2.1 2.4 2.3 1.9 2.3
## [145] 2.5 2.3 1.9 2.0 2.3 1.8
## using column name
iris[, "Petal.Width"]
## [1] 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 0.2 0.2 0.1 0.1 0.2 0.4 0.4 0.3
## [19] 0.3 0.3 0.2 0.4 0.2 0.5 0.2 0.2 0.4 0.2 0.2 0.2 0.2 0.4 0.1 0.2 0.2 0.2
## [37] 0.2 0.1 0.2 0.2 0.3 0.3 0.2 0.6 0.4 0.3 0.2 0.2 0.2 0.2 1.4 1.5 1.5 1.3
## [55] 1.5 1.3 1.6 1.0 1.3 1.4 1.0 1.5 1.0 1.4 1.3 1.4 1.5 1.0 1.5 1.1 1.8 1.3
## [73] 1.5 1.2 1.3 1.4 1.4 1.7 1.5 1.0 1.1 1.0 1.2 1.6 1.5 1.6 1.5 1.3 1.3 1.3
## [91] 1.2 1.4 1.2 1.0 1.3 1.2 1.3 1.3 1.1 1.3 2.5 1.9 2.1 1.8 2.2 2.1 1.7 1.8
## [109] 1.8 2.5 2.0 1.9 2.1 2.0 2.4 2.3 1.8 2.2 2.3 1.5 2.3 2.0 2.0 1.8 2.1 1.8
## [127] 1.8 1.8 2.1 1.6 1.9 2.0 2.2 1.5 1.4 2.3 2.4 1.8 1.8 2.1 2.4 2.3 1.9 2.3
## [145] 2.5 2.3 1.9 2.0 2.3 1.8
## using column name and $ operator
iris$Petal.Width
## [1] 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 0.2 0.2 0.1 0.1 0.2 0.4 0.4 0.3
## [19] 0.3 0.3 0.2 0.4 0.2 0.5 0.2 0.2 0.4 0.2 0.2 0.2 0.2 0.4 0.1 0.2 0.2 0.2
## [37] 0.2 0.1 0.2 0.2 0.3 0.3 0.2 0.6 0.4 0.3 0.2 0.2 0.2 0.2 1.4 1.5 1.5 1.3
## [55] 1.5 1.3 1.6 1.0 1.3 1.4 1.0 1.5 1.0 1.4 1.3 1.4 1.5 1.0 1.5 1.1 1.8 1.3
## [73] 1.5 1.2 1.3 1.4 1.4 1.7 1.5 1.0 1.1 1.0 1.2 1.6 1.5 1.6 1.5 1.3 1.3 1.3
## [91] 1.2 1.4 1.2 1.0 1.3 1.2 1.3 1.3 1.1 1.3 2.5 1.9 2.1 1.8 2.2 2.1 1.7 1.8
## [109] 1.8 2.5 2.0 1.9 2.1 2.0 2.4 2.3 1.8 2.2 2.3 1.5 2.3 2.0 2.0 1.8 2.1 1.8
## [127] 1.8 1.8 2.1 1.6 1.9 2.0 2.2 1.5 1.4 2.3 2.4 1.8 1.8 2.1 2.4 2.3 1.9 2.3
## [145] 2.5 2.3 1.9 2.0 2.3 1.8
## like a list
iris[[4]]
## [1] 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 0.2 0.2 0.1 0.1 0.2 0.4 0.4 0.3
## [19] 0.3 0.3 0.2 0.4 0.2 0.5 0.2 0.2 0.4 0.2 0.2 0.2 0.2 0.4 0.1 0.2 0.2 0.2
## [37] 0.2 0.1 0.2 0.2 0.3 0.3 0.2 0.6 0.4 0.3 0.2 0.2 0.2 0.2 1.4 1.5 1.5 1.3
## [55] 1.5 1.3 1.6 1.0 1.3 1.4 1.0 1.5 1.0 1.4 1.3 1.4 1.5 1.0 1.5 1.1 1.8 1.3
## [73] 1.5 1.2 1.3 1.4 1.4 1.7 1.5 1.0 1.1 1.0 1.2 1.6 1.5 1.6 1.5 1.3 1.3 1.3
## [91] 1.2 1.4 1.2 1.0 1.3 1.2 1.3 1.3 1.1 1.3 2.5 1.9 2.1 1.8 2.2 2.1 1.7 1.8
## [109] 1.8 2.5 2.0 1.9 2.1 2.0 2.4 2.3 1.8 2.2 2.3 1.5 2.3 2.0 2.0 1.8 2.1 1.8
## [127] 1.8 1.8 2.1 1.6 1.9 2.0 2.2 1.5 1.4 2.3 2.4 1.8 1.8 2.1 2.4 2.3 1.9 2.3
## [145] 2.5 2.3 1.9 2.0 2.3 1.8
Species
and Sepal.Width columns of the iris object in the console.iris[1:5, c("Sepal.Width", "Species")]
## Sepal.Width Species
## 1 3.5 setosa
## 2 3.0 setosa
## 3 3.2 setosa
## 4 3.1 setosa
## 5 3.6 setosa
iris dataset in the console with the columns
displayed in alphabetical order. This can be done using the sort()
function. Use the result of sort(colnames(iris)) along with []
to select the columns in alphabetical order.iris[, sort(colnames(iris))]
## Petal.Length Petal.Width Sepal.Length Sepal.Width Species
## 1 1.4 0.2 5.1 3.5 setosa
## 2 1.4 0.2 4.9 3.0 setosa
## 3 1.3 0.2 4.7 3.2 setosa
## 4 1.5 0.2 4.6 3.1 setosa
## 5 1.4 0.2 5.0 3.6 setosa
## 6 1.7 0.4 5.4 3.9 setosa
## 7 1.4 0.3 4.6 3.4 setosa
## 8 1.5 0.2 5.0 3.4 setosa
## 9 1.4 0.2 4.4 2.9 setosa
## 10 1.5 0.1 4.9 3.1 setosa
## 11 1.5 0.2 5.4 3.7 setosa
## 12 1.6 0.2 4.8 3.4 setosa
## 13 1.4 0.1 4.8 3.0 setosa
## 14 1.1 0.1 4.3 3.0 setosa
## 15 1.2 0.2 5.8 4.0 setosa
## 16 1.5 0.4 5.7 4.4 setosa
## 17 1.3 0.4 5.4 3.9 setosa
## 18 1.4 0.3 5.1 3.5 setosa
## 19 1.7 0.3 5.7 3.8 setosa
## 20 1.5 0.3 5.1 3.8 setosa
## 21 1.7 0.2 5.4 3.4 setosa
## 22 1.5 0.4 5.1 3.7 setosa
## 23 1.0 0.2 4.6 3.6 setosa
## 24 1.7 0.5 5.1 3.3 setosa
## 25 1.9 0.2 4.8 3.4 setosa
## 26 1.6 0.2 5.0 3.0 setosa
## 27 1.6 0.4 5.0 3.4 setosa
## 28 1.5 0.2 5.2 3.5 setosa
## 29 1.4 0.2 5.2 3.4 setosa
## 30 1.6 0.2 4.7 3.2 setosa
## 31 1.6 0.2 4.8 3.1 setosa
## 32 1.5 0.4 5.4 3.4 setosa
## 33 1.5 0.1 5.2 4.1 setosa
## 34 1.4 0.2 5.5 4.2 setosa
## 35 1.5 0.2 4.9 3.1 setosa
## 36 1.2 0.2 5.0 3.2 setosa
## 37 1.3 0.2 5.5 3.5 setosa
## 38 1.4 0.1 4.9 3.6 setosa
## 39 1.3 0.2 4.4 3.0 setosa
## 40 1.5 0.2 5.1 3.4 setosa
## 41 1.3 0.3 5.0 3.5 setosa
## 42 1.3 0.3 4.5 2.3 setosa
## 43 1.3 0.2 4.4 3.2 setosa
## 44 1.6 0.6 5.0 3.5 setosa
## 45 1.9 0.4 5.1 3.8 setosa
## 46 1.4 0.3 4.8 3.0 setosa
## 47 1.6 0.2 5.1 3.8 setosa
## 48 1.4 0.2 4.6 3.2 setosa
## 49 1.5 0.2 5.3 3.7 setosa
## 50 1.4 0.2 5.0 3.3 setosa
## 51 4.7 1.4 7.0 3.2 versicolor
## 52 4.5 1.5 6.4 3.2 versicolor
## 53 4.9 1.5 6.9 3.1 versicolor
## 54 4.0 1.3 5.5 2.3 versicolor
## 55 4.6 1.5 6.5 2.8 versicolor
## 56 4.5 1.3 5.7 2.8 versicolor
## 57 4.7 1.6 6.3 3.3 versicolor
## 58 3.3 1.0 4.9 2.4 versicolor
## 59 4.6 1.3 6.6 2.9 versicolor
## 60 3.9 1.4 5.2 2.7 versicolor
## 61 3.5 1.0 5.0 2.0 versicolor
## 62 4.2 1.5 5.9 3.0 versicolor
## 63 4.0 1.0 6.0 2.2 versicolor
## 64 4.7 1.4 6.1 2.9 versicolor
## 65 3.6 1.3 5.6 2.9 versicolor
## 66 4.4 1.4 6.7 3.1 versicolor
## 67 4.5 1.5 5.6 3.0 versicolor
## 68 4.1 1.0 5.8 2.7 versicolor
## 69 4.5 1.5 6.2 2.2 versicolor
## 70 3.9 1.1 5.6 2.5 versicolor
## 71 4.8 1.8 5.9 3.2 versicolor
## 72 4.0 1.3 6.1 2.8 versicolor
## 73 4.9 1.5 6.3 2.5 versicolor
## 74 4.7 1.2 6.1 2.8 versicolor
## 75 4.3 1.3 6.4 2.9 versicolor
## 76 4.4 1.4 6.6 3.0 versicolor
## 77 4.8 1.4 6.8 2.8 versicolor
## 78 5.0 1.7 6.7 3.0 versicolor
## 79 4.5 1.5 6.0 2.9 versicolor
## 80 3.5 1.0 5.7 2.6 versicolor
## 81 3.8 1.1 5.5 2.4 versicolor
## 82 3.7 1.0 5.5 2.4 versicolor
## 83 3.9 1.2 5.8 2.7 versicolor
## 84 5.1 1.6 6.0 2.7 versicolor
## 85 4.5 1.5 5.4 3.0 versicolor
## 86 4.5 1.6 6.0 3.4 versicolor
## 87 4.7 1.5 6.7 3.1 versicolor
## 88 4.4 1.3 6.3 2.3 versicolor
## 89 4.1 1.3 5.6 3.0 versicolor
## 90 4.0 1.3 5.5 2.5 versicolor
## 91 4.4 1.2 5.5 2.6 versicolor
## 92 4.6 1.4 6.1 3.0 versicolor
## 93 4.0 1.2 5.8 2.6 versicolor
## 94 3.3 1.0 5.0 2.3 versicolor
## 95 4.2 1.3 5.6 2.7 versicolor
## 96 4.2 1.2 5.7 3.0 versicolor
## 97 4.2 1.3 5.7 2.9 versicolor
## 98 4.3 1.3 6.2 2.9 versicolor
## 99 3.0 1.1 5.1 2.5 versicolor
## 100 4.1 1.3 5.7 2.8 versicolor
## 101 6.0 2.5 6.3 3.3 virginica
## 102 5.1 1.9 5.8 2.7 virginica
## 103 5.9 2.1 7.1 3.0 virginica
## 104 5.6 1.8 6.3 2.9 virginica
## 105 5.8 2.2 6.5 3.0 virginica
## 106 6.6 2.1 7.6 3.0 virginica
## 107 4.5 1.7 4.9 2.5 virginica
## 108 6.3 1.8 7.3 2.9 virginica
## 109 5.8 1.8 6.7 2.5 virginica
## 110 6.1 2.5 7.2 3.6 virginica
## 111 5.1 2.0 6.5 3.2 virginica
## 112 5.3 1.9 6.4 2.7 virginica
## 113 5.5 2.1 6.8 3.0 virginica
## 114 5.0 2.0 5.7 2.5 virginica
## 115 5.1 2.4 5.8 2.8 virginica
## 116 5.3 2.3 6.4 3.2 virginica
## 117 5.5 1.8 6.5 3.0 virginica
## 118 6.7 2.2 7.7 3.8 virginica
## 119 6.9 2.3 7.7 2.6 virginica
## 120 5.0 1.5 6.0 2.2 virginica
## 121 5.7 2.3 6.9 3.2 virginica
## 122 4.9 2.0 5.6 2.8 virginica
## 123 6.7 2.0 7.7 2.8 virginica
## 124 4.9 1.8 6.3 2.7 virginica
## 125 5.7 2.1 6.7 3.3 virginica
## 126 6.0 1.8 7.2 3.2 virginica
## 127 4.8 1.8 6.2 2.8 virginica
## 128 4.9 1.8 6.1 3.0 virginica
## 129 5.6 2.1 6.4 2.8 virginica
## 130 5.8 1.6 7.2 3.0 virginica
## 131 6.1 1.9 7.4 2.8 virginica
## 132 6.4 2.0 7.9 3.8 virginica
## 133 5.6 2.2 6.4 2.8 virginica
## 134 5.1 1.5 6.3 2.8 virginica
## 135 5.6 1.4 6.1 2.6 virginica
## 136 6.1 2.3 7.7 3.0 virginica
## 137 5.6 2.4 6.3 3.4 virginica
## 138 5.5 1.8 6.4 3.1 virginica
## 139 4.8 1.8 6.0 3.0 virginica
## 140 5.4 2.1 6.9 3.1 virginica
## 141 5.6 2.4 6.7 3.1 virginica
## 142 5.1 2.3 6.9 3.1 virginica
## 143 5.1 1.9 5.8 2.7 virginica
## 144 5.9 2.3 6.8 3.2 virginica
## 145 5.7 2.5 6.7 3.3 virginica
## 146 5.2 2.3 6.7 3.0 virginica
## 147 5.0 1.9 6.3 2.5 virginica
## 148 5.2 2.0 6.5 3.0 virginica
## 149 5.4 2.3 6.2 3.4 virginica
## 150 5.1 1.8 5.9 3.0 virginica