Overview of DataFrames
A DataFrame is a two-dimensional data container, similar to a Matrix, but which can contain heterogeneous data, and for which symbolic names may be associated with the rows and columns.
Each column of a DataFrame is a DataSeries, and the column labels may be used to refer to the corresponding column.
df := DataFrame( < 1, 2, 3; 4, 5, 6 >, 'rows' = [ 'a', 'b' ], 'columns' = [ 'A', 'B', 'C' ] );
type( df[ 'B' ], DataSeries );
Since each column is a DataSeries, you can index hierarchically into the columns of a DataFrame to extract individual data elements.
df[ 'B' ][ 1 ];
df[ 'B' ][ 'b' ];
However, you can also select individual data items by specifying the desired row and column indices directly. (Row and column indices may be either numeric, by position, or symbolic.)
df[ 1, 2 ];
df[ 'a', 'B' ];
You can use a range or list to select specified columns. In the case of a list, they can come in any desired order.
df[ 'A' .. 'B'];
df[ [ 'B', 'C', 'A' ] ];
For more information on indexing a DataFrame, see DataFrame,indexing.
Statistics with DataFrames
Subsets of DataFrames
A Guide to Data Frames
Download Help Document
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