Read and save

Aim of the Unit

This Unit aims to:

  1. Import the dataset from a file
  2. Save the dataset to a file

Functions to read and save data

R has dedicated functions to load and save data:

Function Arguments Description
read.csv()
file = "" Type the name of the file with the extension (i.e. file = "data.csv")
header = TRUE With TRUE, the first raw is treated as Header.
sep = ";" This specifies which symbol is used to separate columns (i.e. ";" or ",")
dec = "." This specifies which symbol is used for decimals (i.e. "." or ",")
write.csv()
col.names = TRUE
sep = ";" as before
dec = "." as before

To load data:

setwd("C:/R_prova") # This is the adress to the folder where the files are located
X <- read.csv("data.csv", sep = ",", dec = ".")

which gives:

X.1 X Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1 1 5.1 3.5 1.4 0.2 setosa
2 2 4.9 3.0 1.4 0.2 setosa
3 3 4.7 3.2 1.3 0.2 setosa
4 4 4.6 3.1 1.5 0.2 setosa
5 5 5.0 3.6 1.4 0.2 setosa
6 6 5.4 3.9 1.7 0.4 setosa
7 7 4.6 3.4 1.4 0.3 setosa
8 8 5.0 3.4 1.5 0.2 setosa
9 9 4.4 2.9 1.4 0.2 setosa
10 10 4.9 3.1 1.5 0.1 setosa
11 11 5.4 3.7 1.5 0.2 setosa
12 12 4.8 3.4 1.6 0.2 setosa
13 13 4.8 3.0 1.4 0.1 setosa
14 14 4.3 3.0 1.1 0.1 setosa
15 15 5.8 4.0 1.2 0.2 setosa
16 16 5.7 4.4 1.5 0.4 setosa
17 17 5.4 3.9 1.3 0.4 setosa
18 18 5.1 3.5 1.4 0.3 setosa
19 19 5.7 3.8 1.7 0.3 setosa
20 20 5.1 3.8 1.5 0.3 setosa
21 21 5.4 3.4 1.7 0.2 setosa
22 22 5.1 3.7 1.5 0.4 setosa
23 23 4.6 3.6 1.0 0.2 setosa
24 24 5.1 3.3 1.7 0.5 setosa
25 25 4.8 3.4 1.9 0.2 setosa
26 26 5.0 3.0 1.6 0.2 setosa
27 27 5.0 3.4 1.6 0.4 setosa
28 28 5.2 3.5 1.5 0.2 setosa
29 29 5.2 3.4 1.4 0.2 setosa
30 30 4.7 3.2 1.6 0.2 setosa
31 31 4.8 3.1 1.6 0.2 setosa
32 32 5.4 3.4 1.5 0.4 setosa
33 33 5.2 4.1 1.5 0.1 setosa
34 34 5.5 4.2 1.4 0.2 setosa
35 35 4.9 3.1 1.5 0.2 setosa
36 36 5.0 3.2 1.2 0.2 setosa
37 37 5.5 3.5 1.3 0.2 setosa
38 38 4.9 3.6 1.4 0.1 setosa
39 39 4.4 3.0 1.3 0.2 setosa
40 40 5.1 3.4 1.5 0.2 setosa
41 41 5.0 3.5 1.3 0.3 setosa
42 42 4.5 2.3 1.3 0.3 setosa
43 43 4.4 3.2 1.3 0.2 setosa
44 44 5.0 3.5 1.6 0.6 setosa
45 45 5.1 3.8 1.9 0.4 setosa
46 46 4.8 3.0 1.4 0.3 setosa
47 47 5.1 3.8 1.6 0.2 setosa
48 48 4.6 3.2 1.4 0.2 setosa
49 49 5.3 3.7 1.5 0.2 setosa
50 50 5.0 3.3 1.4 0.2 setosa
51 51 7.0 3.2 4.7 1.4 versicolor
52 52 6.4 3.2 4.5 1.5 versicolor
53 53 6.9 3.1 4.9 1.5 versicolor
54 54 5.5 2.3 4.0 1.3 versicolor
55 55 6.5 2.8 4.6 1.5 versicolor
56 56 5.7 2.8 4.5 1.3 versicolor
57 57 6.3 3.3 4.7 1.6 versicolor
58 58 4.9 2.4 3.3 1.0 versicolor
59 59 6.6 2.9 4.6 1.3 versicolor
60 60 5.2 2.7 3.9 1.4 versicolor
61 61 5.0 2.0 3.5 1.0 versicolor
62 62 5.9 3.0 4.2 1.5 versicolor
63 63 6.0 2.2 4.0 1.0 versicolor
64 64 6.1 2.9 4.7 1.4 versicolor
65 65 5.6 2.9 3.6 1.3 versicolor
66 66 6.7 3.1 4.4 1.4 versicolor
67 67 5.6 3.0 4.5 1.5 versicolor
68 68 5.8 2.7 4.1 1.0 versicolor
69 69 6.2 2.2 4.5 1.5 versicolor
70 70 5.6 2.5 3.9 1.1 versicolor
71 71 5.9 3.2 4.8 1.8 versicolor
72 72 6.1 2.8 4.0 1.3 versicolor
73 73 6.3 2.5 4.9 1.5 versicolor
74 74 6.1 2.8 4.7 1.2 versicolor
75 75 6.4 2.9 4.3 1.3 versicolor
76 76 6.6 3.0 4.4 1.4 versicolor
77 77 6.8 2.8 4.8 1.4 versicolor
78 78 6.7 3.0 5.0 1.7 versicolor
79 79 6.0 2.9 4.5 1.5 versicolor
80 80 5.7 2.6 3.5 1.0 versicolor
81 81 5.5 2.4 3.8 1.1 versicolor
82 82 5.5 2.4 3.7 1.0 versicolor
83 83 5.8 2.7 3.9 1.2 versicolor
84 84 6.0 2.7 5.1 1.6 versicolor
85 85 5.4 3.0 4.5 1.5 versicolor
86 86 6.0 3.4 4.5 1.6 versicolor
87 87 6.7 3.1 4.7 1.5 versicolor
88 88 6.3 2.3 4.4 1.3 versicolor
89 89 5.6 3.0 4.1 1.3 versicolor
90 90 5.5 2.5 4.0 1.3 versicolor
91 91 5.5 2.6 4.4 1.2 versicolor
92 92 6.1 3.0 4.6 1.4 versicolor
93 93 5.8 2.6 4.0 1.2 versicolor
94 94 5.0 2.3 3.3 1.0 versicolor
95 95 5.6 2.7 4.2 1.3 versicolor
96 96 5.7 3.0 4.2 1.2 versicolor
97 97 5.7 2.9 4.2 1.3 versicolor
98 98 6.2 2.9 4.3 1.3 versicolor
99 99 5.1 2.5 3.0 1.1 versicolor
100 100 5.7 2.8 4.1 1.3 versicolor
101 101 6.3 3.3 6.0 2.5 virginica
102 102 5.8 2.7 5.1 1.9 virginica
103 103 7.1 3.0 5.9 2.1 virginica
104 104 6.3 2.9 5.6 1.8 virginica
105 105 6.5 3.0 5.8 2.2 virginica
106 106 7.6 3.0 6.6 2.1 virginica
107 107 4.9 2.5 4.5 1.7 virginica
108 108 7.3 2.9 6.3 1.8 virginica
109 109 6.7 2.5 5.8 1.8 virginica
110 110 7.2 3.6 6.1 2.5 virginica
111 111 6.5 3.2 5.1 2.0 virginica
112 112 6.4 2.7 5.3 1.9 virginica
113 113 6.8 3.0 5.5 2.1 virginica
114 114 5.7 2.5 5.0 2.0 virginica
115 115 5.8 2.8 5.1 2.4 virginica
116 116 6.4 3.2 5.3 2.3 virginica
117 117 6.5 3.0 5.5 1.8 virginica
118 118 7.7 3.8 6.7 2.2 virginica
119 119 7.7 2.6 6.9 2.3 virginica
120 120 6.0 2.2 5.0 1.5 virginica
121 121 6.9 3.2 5.7 2.3 virginica
122 122 5.6 2.8 4.9 2.0 virginica
123 123 7.7 2.8 6.7 2.0 virginica
124 124 6.3 2.7 4.9 1.8 virginica
125 125 6.7 3.3 5.7 2.1 virginica
126 126 7.2 3.2 6.0 1.8 virginica
127 127 6.2 2.8 4.8 1.8 virginica
128 128 6.1 3.0 4.9 1.8 virginica
129 129 6.4 2.8 5.6 2.1 virginica
130 130 7.2 3.0 5.8 1.6 virginica
131 131 7.4 2.8 6.1 1.9 virginica
132 132 7.9 3.8 6.4 2.0 virginica
133 133 6.4 2.8 5.6 2.2 virginica
134 134 6.3 2.8 5.1 1.5 virginica
135 135 6.1 2.6 5.6 1.4 virginica
136 136 7.7 3.0 6.1 2.3 virginica
137 137 6.3 3.4 5.6 2.4 virginica
138 138 6.4 3.1 5.5 1.8 virginica
139 139 6.0 3.0 4.8 1.8 virginica
140 140 6.9 3.1 5.4 2.1 virginica
141 141 6.7 3.1 5.6 2.4 virginica
142 142 6.9 3.1 5.1 2.3 virginica
143 143 5.8 2.7 5.1 1.9 virginica
144 144 6.8 3.2 5.9 2.3 virginica
145 145 6.7 3.3 5.7 2.5 virginica
146 146 6.7 3.0 5.2 2.3 virginica
147 147 6.3 2.5 5.0 1.9 virginica
148 148 6.5 3.0 5.2 2.0 virginica
149 149 6.2 3.4 5.4 2.3 virginica
150 150 5.9 3.0 5.1 1.8 virginica

To save data:

write.csv(x, "data.csv")

To save it in a different folder:

write.csv(x = X, file = "C://R_prova/data.csv")