R: Multiplicities of (x,y) Points, e.g., for a Sunflower Plot

xyTable {grDevices}

R Documentation

Multiplicities of (x,y) Points, e.g., for a Sunflower Plot

Description

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.

Usage

xyTable(x, y = NULL, digits)

Arguments

`x,y`	numeric vectors of the same length; alternatively other (x,y) argument combinations as allowed by `xy.coords(x,y)`.
`digits`	integer specifying the significant digits to be used for determining equality of coordinates. These are compared after rounding them via `signif(*,digits)`.

Value

A list with three components of same length,

`x`	x coordinates, rounded and sorted.
`y`	y coordinates, rounded (and sorted within `x`).
`number`	multiplicities (positive integers); i.e., `number[i]` is the multiplicity of `(x[i],y[i])`.

Examples

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)