cut.mondate: Convert a mondate Object to a Factor
In mondate: Keep Track of Dates in Terms of Months

Description Usage Arguments Details Value Author(s) See Also Examples

Method for cut applied to mondate objects.

 ## S3 method for class 'mondate'
cut(x, breaks, labels = NULL, 
      include.lowest = TRUE, right = TRUE, 
      start.on.monday = TRUE, attr.breaks = FALSE, ...)

`x`	a `mondate`
`breaks`	a vector of cut points or number giving the number of intervals which x is to be cut into or an interval specification, one of "day", "week", "month", "quarter" or "year", optionally preceded by an integer and a space, or followed by "s" (pluralized).
`labels`	labels for the levels of the resulting category. By default, labels are constructed from the right-hand end of the intervals (which are included for the default value of right). If `labels = FALSE`, simple integer codes are returned instead of a factor.
`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.
`start.on.monday`	logical. If `breaks = "weeks"`, should the week start on Mondays or Sundays?
`attr.breaks`	logical. If `TRUE` the result has a "breaks" attribute which is a `mondate` whose pairwise values determine a covering of `x`. Most helpful when `breaks` = "days", "weeks", "months", "quarters", or "years".
`...`	optional arguments passed to or from other methods.

Convert a mondate to a factor where, in the "end-of-business-day" spirit of mondate, the levels are labeled by the last day in the period. If right = FALSE the levels are labeled by the first day in the period.

For numeric breaks – which case also includes mondates – the method calls cut.default and the intervals encoded in the levels are converted to date format using mondate logic. In the spirit of mondate, the default right = TRUE ensures that the intervals are left-open/right-closed. The default include.lowest = TRUE ensures that min(x) is included in the first interval.

For breaks = "days" or "weeks", the method calls cut(as.Date(x)). For breaks = "months", "quarters", and "years", numeric breaks are determined from the range of x.

If breaks is preceded by an integer, call it step, then the period of the first level is determined by min(x) and subsequent "day", "week", "month", "quarter", and "year" periods are determined sequentially per seq(min(x), max(x), by = step).

When attr.breaks = TRUE, the result will have a "breaks" attribute (attr(., "breaks")) which pairwise "cover" x. Such "breaks" are suitable be use by 'hist', for example.

In all cases, the formats of the dates representing the levels are inherited from displayFormat(x). Accordingly, if such resulting potential levels would be non-unique, cut.mondate resorts to the fall-back scheme of cut.default, i.e., "labels such as "Range3" will be used."

A factor is returned, unless labels = FALSE which returns the integer level codes.

Dan Murphy. Many thanks to the R-development team for cut and cut.Date.

cut and cut.Date

x <- mondate(0:12)
cut(x, breaks = 4)
cut(x, mondate.ymd(1999) + c(0, 3, 6, 9, 12)) # same as above

# days
x <- mondate.ymd(2013, 1, 1:7)
cut(x, breaks = "days")

# weeks
x <- mondate.ymd(2013, 1, 1:31)  # days in January 2013
cut(x, breaks = "weeks") # labeled by the first 5 Sundays of 2013
cut(x, breaks = "2 weeks") # labeled by 2nd, 4th, and 6th Sundays of 2013

# months
x <- mondate.ymd(2013, 1:12, 15) # 15th day of each month in 2013
cut(x, breaks = "months") # labeled by last day of the month
cut(x, breaks = "months", right = FALSE) # labeled by first day of the month
cut(x, breaks = "2 months") # labeled by last day of the month
x1 <- mondate.ymd(2008, 6)
x2 <- mondate.ymd(2008:2011, 6)
cx1 <- cut(x1, "month", right = FALSE)
cx2 <- cut(x2, "month", right = FALSE)
stopifnot(levels(cx1)[cx1] == levels(cx2)[cx2[1]])

# quarters
x <- mondate.ymd(2013, 1:12, 15) # 15th day of each month in 2013
cut(x, "quarters")       # labeled by last day of the quarter
cut(x, "quarters", right = FALSE) # labeled by first day of the quarter
cut(x, "2 quarters")
cut(x, "2 quarters", right = FALSE) # labeled by first day of the quarter

# years
m <- mondate(0:12)
cut(m, "years")           # labeled by last day of the year
cut(m, "years", right = FALSE) # labeled by last day of the year
displayFormat(m) <- "%Y"
cut(m, "years")           # labeled by just the year
x <- mondate.ymd(2008:2013, 6)
cut(x, "years")                  # 6 levels labeled by last day of the year
cut(x, "years", right = FALSE)   # 6 levels labeled by first day of the year
cut(x, "3 years")                # 2 levels
cut(x, "3 years", right = FALSE) # 2 levels
x1 <- mondate.ymd(2008, 12)
x2 <- mondate.ymd(2008:2011, 12)
cx1 <- cut(x1, "year", right = FALSE)
cx2 <- cut(x2, "year", right = FALSE)
stopifnot(levels(cx1)[cx1] == levels(cx2)[cx2[1]])