C_07_shingles {lattice} | R Documentation

## shingles

### Description

Functions to handle shingles

### Usage

    shingle(x, intervals=sort(unique(x)))
    equal.count(x, ...)
    as.shingle(x)
    is.shingle(x)

    ## S3 method for class 'shingle'
    plot(x, panel, xlab, ylab, ...)

    ## S3 method for class 'shingle'
    print(x, showValues = TRUE, ...)

    ## S3 method for class 'shingleLevel'
    as.character(x, ...)

    ## S3 method for class 'shingleLevel'
    print(x, ...)

    ## S3 method for class 'shingle'
    summary(object, showValues = FALSE, ...)

    ## S3 method for class 'shingle'
    x[subset, drop = FALSE]
    as.factorOrShingle(x, subset, drop)

### Arguments

`x` | numeric variable or R object, shingle in `plot.shingle` and `x[]`. An object (list of intervals) of class "shingleLevel" in `print.shingleLevel`
`object` | shingle object to be summarized
`showValues` | logical, whether to print the numeric part. If FALSE, only the intervals are printed

`intervals` | numeric vector or matrix with 2 columns
`subset` | logical vector
`drop` | whether redundant shingle levels are to be dropped
`panel, xlab, ylab` | standard Trellis arguments (see `xyplot` )
`...` | other arguments, passed down as appropriate. For example, extra arguments to `equal.count` are passed on to `co.intervals`. graphical parameters can be passed as arguments to the `plot` method.

### Details

A shingle is a data structure used in Trellis, and is a generalization of factors to ‘continuous’ variables. It consists of a numeric vector along with some possibly overlapping intervals. These intervals are the ‘levels’ of the shingle. The `levels` and `nlevels` functions, usually applicable to factors, also work on shingles. The implementation of shingles is slightly different from S.

There are print methods for shingles, as well as for printing the result of `levels()` applied to a shingle. For use in labelling, the `as.character` method can be used to convert levels of a shingle to character strings.

`equal.count` converts `x` to a shingle using the equal count algorithm. This is essentially a wrapper around `co.intervals`. All arguments are passed to `co.intervals`.

`shingle` creates a shingle using the given `intervals`. If `intervals` is a vector, these are used to form 0 length intervals.

`as.shingle` returns `shingle(x)` if `x` is not a shingle.

`is.shingle` tests whether `x` is a shingle.

`plot.shingle` displays the ranges of shingles via rectangles. `print.shingle` and `summary.shingle` describe the shingle object.

### Value

`x$intervals` for `levels.shingle(x)`, logical for `is.shingle`, an object of class `"trellis"` for `plot` (printed by default by `print.trellis`), and an object of class `"shingle"` for the others.

### Author(s)

Deepayan Sarkar Deepayan.Sarkar@R-project.org

### See Also

`xyplot`, `co.intervals`, `Lattice`

### Examples

    z <- equal.count(rnorm(50))
    plot(z)
    print(z)
    print(levels(z))

[Package lattice version 0.20-6 Index]