The notation, women{datasets}, indicates that a data object by the name women is in the datasets package. This package is preloaded when R is invoked. Explain the difference between c(women) and c(as.matrix(women)) using the women{datasets}.
datasets::women
#> height weight
#> 1 58 115
#> 2 59 117
#> 3 60 120
#> 4 61 123
#> 5 62 126
#> 6 63 129
#> 7 64 132
#> 8 65 135
#> 9 66 139
#> 10 67 142
#> 11 68 146
#> 12 69 150
#> 13 70 154
#> 14 71 159
#> 15 72 164
str(women)
#> 'data.frame': 15 obs. of 2 variables:
#> $ height: num 58 59 60 61 62 63 64 65 66 67 ...
#> $ weight: num 115 117 120 123 126 129 132 135 139 142 ...c(women)
#> $height
#> [1] 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72
#>
#> $weight
#> [1] 115 117 120 123 126 129 132 135 139 142 146 150 154 159 164c(women)是將women{datasets}視為dataframe，並把當中的列(column)資料(為height和weight二列)各自挑出來呈現。
c(as.matrix(women))
#> [1] 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 115 117 120 123
#> [20] 126 129 132 135 139 142 146 150 154 159 164c(as.matrix(women))則是將women{datasets}看作是一15*2的矩陣(matrix)，所挑出來的資料為此矩陣中各個元素，按照順序排列呈現。