Cut an Integer Variable into Intervals

A cut() method for integer vectors. cut.default() labels its intervals in the mathematical "(a,b]" notation, which is right for a continuous variable but reads awkwardly for counts: for integers, "11-20" says the same thing more plainly than "(10,20]".

Usage

# S3 method for class 'integer'
cut(
  x,
  breaks,
  labels = NULL,
  include.lowest = FALSE,
  right = TRUE,
  ordered_result = FALSE,
  ...
)

Arguments

x

an integer vector

breaks

either a vector of cut points or a single number giving the number of intervals

labels

labels for the levels. The integer-style labels described above are used when this is NULL.

include.lowest, right, ordered_result, ...

passed to cut.default()

Value

a factor of the same length as x

Details

The integer labels are only constructed when labels is NULL and breaks is a vector of whole numbers. A scalar breaks (a number of intervals) is passed straight to cut.default(), which computes the cut points itself, and fractional break points fall back to the default interval notation as well - "34.3-66.6" would suggest an integer range that does not exist.

Infinite outer breaks are rendered as "..", so breaks = c(0, 10, Inf) yields "1-10" and "11-..".

See also

cut(), cutAge(), cutQ()

Other cut: cutAge(), cutQ()

Examples

x <- as.integer(c(1, 5, 10, 11, 20, 21))

cut(x, breaks = c(0, 10, 20, Inf))
#> [1] 1-10  1-10  1-10  11-20 11-20 21-..
#> Levels: 1-10 11-20 21-..

# left-closed intervals shift the labels accordingly
cut(x, breaks = c(0, 10, 20, Inf), right = FALSE)
#> [1] 0-9   0-9   10-19 10-19 20-.. 20-..
#> Levels: 0-9 10-19 20-..

# a scalar breaks is left to cut.default()
cut(x, breaks = 3)
#> [1] (0.98,7.67] (0.98,7.67] (7.67,14.3] (7.67,14.3] (14.3,21]   (14.3,21]  
#> Levels: (0.98,7.67] (7.67,14.3] (14.3,21]