The DataFrameR, C
class represents a data set that consists of multiple variables that
may have different element types. The columns in a data frame are generic vectors.
All columns have the same number of observations.
The rows and columns of a data frame can be accessed by position or by key.
The collection of row keys or column keys is called
A data frame has a row index and a column index.
Indexes were discussed in the previous section.
In this section: