Quickly cut a vector with the Jenks/Fisher algorithms

Given a numeric vector, this returns a factor of those values cut into n number of breaks using the Jenks/Fisher algorithms. The algorithm(s) sets breaks in a way that highlights very high or very low values well. It's good to use for choropleths that need to convey imbalances or inequities.

Usage

jenks(x, n = 5, true_jenks = FALSE, labels = NULL, ...)

Arguments

x

A numeric vector to cut

n

Number of bins, Default: 5

true_jenks

Logical: should a "true" Jenks algorithm be used? If false, uses the faster Fisher-Jenks algorithm. See classInt::classIntervals() docs for discussion. Default: FALSE

labels

A string vector to be used as bin labels, Default: NULL

...

Arguments passed on to base::cut

breaks

either a numeric vector of two or more unique cut points or a single number (greater than or equal to 2) giving the number of intervals into which x is to be cut.

include.lowest

logical, indicating if an ‘x[i]’ equal to the lowest (or highest, for right = FALSE) ‘breaks’ value should be included.

right

logical, indicating if the intervals should be closed on the right (and open on the left) or vice versa.

dig.lab

integer which is used when labels are not given. It determines the number of digits used in formatting the break numbers.

ordered_result

logical: should the result be an ordered factor?

Value

A factor of the same length as x

See also

classInt::classIntervals()

Examples

set.seed(123)
values <- rexp(30, 0.8)
jenks(values, n = 4)
#>  [1] (0.535,1.36]   (0.535,1.36]   (1.36,2.71]    [0.0364,0.535] [0.0364,0.535]
#>  [6] [0.0364,0.535] [0.0364,0.535] [0.0364,0.535] (2.71,5.05]    [0.0364,0.535]
#> [11] (0.535,1.36]   (0.535,1.36]   [0.0364,0.535] [0.0364,0.535] [0.0364,0.535]
#> [16] (0.535,1.36]   (1.36,2.71]    (0.535,1.36]   (0.535,1.36]   (2.71,5.05]   
#> [21] (0.535,1.36]   (0.535,1.36]   (1.36,2.71]    (1.36,2.71]    (1.36,2.71]   
#> [26] (1.36,2.71]    (1.36,2.71]    (1.36,2.71]    [0.0364,0.535] (0.535,1.36]  
#> Levels: [0.0364,0.535] (0.535,1.36] (1.36,2.71] (2.71,5.05]