Data Exploration

This page shows a basic exploration of iris data with R.

Check the dimensionality

> dim(iris)

[1] 150 5

Variable names or column names

> names(iris)

[1] "Sepal.Length" "Sepal.Width" "Petal.Length" "Petal.Width" "Species"

Structure

> str(iris)

'data.frame': 150 obs. of 5 variables:

$ Sepal.Length: num 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...

$ Sepal.Width : num 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...

$ Petal.Length: num 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...

$ Petal.Width : num 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...

$ Species : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...

Attributes

> attributes(iris)

$names

[1] "Sepal.Length" "Sepal.Width" "Petal.Length" "Petal.Width" "Species"

$row.names

[1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

[21] 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

[41] 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

[61] 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80

[81] 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100

[101] 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120

[121] 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140

[141] 141 142 143 144 145 146 147 148 149 150

$class

[1] "data.frame"

Get the first 5 rows

> iris[1:5,]

Sepal.Length Sepal.Width Petal.Length Petal.Width Species

1 5.1 3.5 1.4 0.2 setosa

2 4.9 3.0 1.4 0.2 setosa

3 4.7 3.2 1.3 0.2 setosa

4 4.6 3.1 1.5 0.2 setosa

5 5.0 3.6 1.4 0.2 setosa

Get Sepal.Length of the first 10 rows

> iris[1:10, "Sepal.Length"]

[1] 5.1 4.9 4.7 4.6 5.0 5.4 4.6 5.0 4.4 4.9

Same as above

> iris$Sepal.Length[1:10]

[1] 5.1 4.9 4.7 4.6 5.0 5.4 4.6 5.0 4.4 4.9

Distribution of every variable

> summary(iris)

Sepal.Length Sepal.Width Petal.Length Petal.Width Species

Min. :4.300 Min. :2.000 Min. :1.000 Min. :0.100 setosa :50

1st Qu.:5.100 1st Qu.:2.800 1st Qu.:1.600 1st Qu.:0.300 versicolor:50

Median :5.800 Median :3.000 Median :4.350 Median :1.300 virginica :50

Mean :5.843 Mean :3.057 Mean :3.758 Mean :1.199

3rd Qu.:6.400 3rd Qu.:3.300 3rd Qu.:5.100 3rd Qu.:1.800

Max. :7.900 Max. :4.400 Max. :6.900 Max. :2.500

Frequency

> table(iris$Species)

setosa versicolor virginica

50 50 50

Pie chart

> pie(table(iris$Species))