

   DDaattaa FFrraammeess

        data.frame(..., row.names = NULL, check.rows = FALSE,
                check.names = TRUE)

        as.data.frame(x)
        is.data.frame(x)

        row.names(data.frame.obj)
        row.names(data.frame.obj) <- names
        print(data.frame.obj, ..., digits = NULL, quote = FALSE, right = TRUE)
        plot (data.frame.obj, ...)

   AArrgguummeennttss::

        ...: these arguments are of either the form `value' or
             `tag=value'.  Component names are created based on
             the tag (if present) or the deparsed argument
             itself.

   row.names: a character vector giving the row names for the
             data frame.

   check.rows: if `TRUE' then the rows are checked for consis-
             tency of length and names.

   check.names: if `TRUE' then the names of the variables in
             the data frame are checked to ensure that they are
             valid variable names.  If necessary they are
             adjusted (by `make.names') so that they are.

   data.frame.obj: objects of class `data.frame'.

        ...: optional arguments to `print' or `plot' methods.

   VVaalluuee::

        For `data.frame(.)' a data frame.  Data frames are the
        fundamental data structure used by most of R's modeling
        software.  They are tightly coupled collections of
        variables which share many of the properties of matri-
        ces.  The main difference being that the columns of a
        data frame may be of differing types (numeric, factor
        and character).

        `as.data.frame' is generic function with many `meth-
        ods'.  It attempts to coerce its argument to be a data
        frame.

        `is.data.frame' returns `TRUE' if its argument is a
        data frame and `FALSE' otherwise.

        `row.names' can be used to set and retrieve the row
        names of a data frame, similarly to `rownames' for
        arrays.

        `plot.data.frame', a method of the `plot' generic, uses
        `stripplot' for one variable, `plot.default' (scatter-
        plot) for two variables, and `pairs' (scatterplot
        matrix) otherwise.

        For the `print' method (`print.data.frame'), see
        `print.matrix'.

        `xpdrows.data.frame' is an auxiliary function which
        expands the rows of a data frame.  It is used by the
        data frame methods of `[<-' and `[[<-' (which perform
        subscripted assignments on a data frame), and not
        intended to be called directly.

   SSeeee AAllssoo::

        `read.table', `Math.data.frame',etc, about Group meth-
        ods for `data.frame's;  `make.names'.

   EExxaammpplleess::

        L3 <- LETTERS[1:3]
        str(d <- data.frame(cbind(x=1, y=1:10), ch=sample(L3, 10, repl=TRUE)))
        str(     data.frame(cbind(  1,   1:10),    sample(L3, 10, repl=TRUE)))
        is.data.frame(d)
        all(1:10 == row.names(d))# TRUE (coercion)

