fastFindInterval: Find Intervals Containing Given Data

In spatstat/spatstat.utils: Utility Functions for 'spatstat'

Find Intervals Containing Given Data

Description

A faster alternative to findInterval for intervals which are equally-spaced.

Usage

fastFindInterval(x, b, labels = FALSE, reltol = 0.001, dig.lab = 3L,
                 left.open=TRUE)

Arguments

x	Data. Numeric vector of values that are to be classified.
b	Breakpoints. Numeric vector of increasing values that are the endpoints of the intervals.
labels	Logical value specifying whether to return a factor, whose levels are the string labels of the intervals.
reltol	Relative tolerance. A positive number.
dig.lab	Integer. Maximum number of digits to use in the labels for the intervals, when labels=TRUE.
left.open	Logical value specifying whether intervals are left-open and right-closed (left.open=TRUE, the default) or left-closed and right-open (left.open=FALSE).

Details

This is an alternative to findInterval(x, b, rightmost.closed=TRUE) which seems to be faster when b is equally spaced and the length of x is large.

If labels=FALSE (the default), the result is an integer vector giving, for each value x[i], the index j of the interval that contains x[i]:

• If left.open=TRUE (the default), the intervals are left-open and right-closed, except for the first interval. This means that x[i] belongs to the jth interval if b[j] < x[i] <= b[j+1] for j > 1 and b[1] <= x[i] <= b[2] for j=1.

• If left.open=FALSE, the intervals are left-closed and right-open, except for the last interval. This means that x[i] belongs to the jth interval if b[j] <= x[i] < b[j+1] for j < m and b[m] <= x[i] <= b[m+1] for j=m where m = length(b)-1 is the number of intervals.

If labels=TRUE, the result is a factor, and the levels are synthetic labels for the intervals, similar to those produced by findInterval.

Note that the default value of left.open is TRUE for fastFindInterval but FALSE for findInterval.

Value

Integer vector, or factor.

Author(s)

\spatstatAuthors

.

See Also

findInterval

Examples

  x <- runif(10)
  b <- seq(0, 1, by=0.2)
  fastFindInterval(x, b, labels=TRUE)

spatstat/spatstat.utils documentation built on April 13, 2025, 12:01 a.m.