R: Create a Factor from a Chron or Dates Object

cut.dates {chron}

R Documentation

Create a Factor from a Chron or Dates Object

Description

Divide the range of a chron or dates object x into intervals and code the values in x according to which interval they fall.

Usage

## S3 method for class 'dates':
cut(x, breaks, labels, start.on.monday = TRUE, ...)

Arguments

`x`	chron or dates object (see `chron`), character dates such as `"10/04/91"` or Julian dates).
`breaks`	either a vector of break points (a `dates` vector, character dates such as `"10/04/91"` or Julian dates), a constant specifying number of equally spaced intervals extending from `min(x)-1` to `max(x)+1`, or one of the strings in `c("days", "weeks", "months", "year")` specifying a time period.
`labels`	character labels for intervals.
`start.on.monday`	should weeks be assumed to start on Mondays? Default is `TRUE`. Set to `FALSE` if weeks start on Sundays; for other days of the week specify the corresponding number: Sunday == 0, Monday == 1, Tuesday == 2, ..., Saturday == 6.
`...`	further arguments to be passed to or from methods.

Value

an ordered factor whose levels represent the various time intervals.

Examples

# days from 07/01/92 thru 07/15/92 fell into 3 Monday-started weeks
cut(dates("07/01/92") + 0:14, "weeks")
# [1] week 1 week 1 week 1 week 1 week 1 week 2 week 2 week 2 
# [9] week 2 week 2 week 2 week 2 week 3 week 3 week 3

dts <- dates(c("02/27/92", "02/27/92", "01/14/92",
               "02/28/92", "02/01/92"))
cut(dts, "months")
# [1] Feb 92 Feb 92 Jan 92 Feb 92 Feb 92
boxplot(runif(5) ~ cut(dts, "months"))