\HeaderA{xyTable}{Multiplicities of (x,y) Points, e.g., for a Sunflower Plot}{xyTable}
\keyword{dplot}{xyTable}
\begin{Description}\relax
Given (x,y) points, determine their multiplicity -- checking for
equality only up to some (crude kind of) noise.  Note that this is
special kind of 2D binning.
\end{Description}
\begin{Usage}
\begin{verbatim}
xyTable(x, y = NULL, digits)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{x,y}] numeric vectors of the same length; alternatively other
(x,y) argument combinations as allowed by \code{\LinkA{xy.coords}{xy.coords}(x,y)}.
\item[\code{digits}] integer specifying the significant digits to be used for
determining equality of coordinates.  These are compared after
rounding them via \code{\LinkA{signif}{signif}(*,digits)}.
\end{ldescription}
\end{Arguments}
\begin{Value}
A list with three components of same length,
\begin{ldescription}
\item[\code{x}] x coordinates, rounded and sorted.
\item[\code{y}] y coordinates, rounded (and sorted within \code{x}).
\item[\code{number}] multiplicities (positive integers); i.e.,
\code{number[i]} is the multiplicity of \code{(x[i],y[i])}.
\end{ldescription}
\end{Value}
\begin{SeeAlso}\relax
\code{\LinkA{sunflowerplot}{sunflowerplot}} which typically uses
\code{xyTable()}; \code{\LinkA{signif}{signif}}.
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
xyTable(iris[,3:4], digits = 6)

## Discretized uncorrelated Gaussian:

require(stats)
xy <- data.frame(x = round(sort(rnorm(100))), y = rnorm(100))
xyTable(xy, digits = 1)
\end{ExampleCode}
\end{Examples}

