niceBreaks: Get nice (symmetric) breaks for an interval

In alexploner/Heatplus: Heatmaps with row and/or column covariates and colored clusters

Description

Given a minimum and a maximum, this function returns a vector of equidistant breaks that covers this interval, and has a pretty interval length (1, 2, or 5 times a power of 10). If the interval contains zero, it will be one of the breaks, so that the intervals are arranged somewhat symmetrically around it.

Usage

niceBreaks(xr, breaks)

Arguments

xr	the range to be covered, as c(min, max)
breaks	either the desired number of breaks, or a pre-specified vector of breaks

Details

The number of desired breaks is honored as far as possible, which is not actually that often in practice. However, major deviations of three or more are reasonably rare.

The functiona allows the specification of a set of breaks instead of the desired number of breaks, somewhat like in cut. However, if the length of breaks is greater than one, the function just sorts the values and returns them otherwise unchanged.

Value

A vector of pretty breaks covering the specified interval, more or less of the desired length.

See Also

pretty

Examples

    
    ## Niceness overrules specified number
    niceBreaks(c(-1,1), 5)
    niceBreaks(c(-1,1), 6)

    ## Zero appears always as break
    niceBreaks(c(-2.75, 1.12), 8)

    ## Not invariant to translation (of course)
    niceBreaks(3.27 + c(-2.75, 1.12), 8)

    

alexploner/Heatplus documentation built on May 23, 2021, 2:01 p.m.