as.ym: A Class for Dealing with the Yearmonth Format

In DescTools: Tools for Descriptive Statistics

A Class for Dealing with the Yearmonth Format

Description

The representation of year and month information in YYYYYMM format as an integer is often handy and a useful and efficient data structure. Adding a number of months to such a date is not quite catchy, however, since the date structure is to be retained. For example, 201201 - 2 [months] is expected to result in 201111 instead of 201199. AddMonthsYM does this job.

Usage

as.ym(x)
## S3 method for class 'ym'
as.Date(x, d = 1, ...)

## S3 method for class 'ym'
AddMonths(x, n, ...)

Arguments

x	a vector of integers, representing the dates in the format YYYYMM, to which a number of months has to be added. YYYY must lie in the range of 1000-3000, MM in 1-12.
d	the day to be used for converting a yearmonth to a date. Default is 1.
n	the number of months to be added. If n is negative the months will be subtracted.
...	further arguments (not used here).

Details

All parameters will be recyled if necessary. The therefore used function mapply will display a warning, if the longer argument is not a multiple of the length of the shorter one.

Value

a vector of class integer with the same dimension as x, containing the transformed dates.

Author(s)

Andri Signorell <[e-mail]>, originally based on code by Roland Rapold

See Also

AddMonths; Date functions, like Year, Month, etc.

Examples

Month(as.ym(202408))
Year(as.ym(202408))

Year(as.Date("2024-12-05"))
Year(as.ym(202412))

Month(as.Date("2024-12-05"), fmt = "mm")
Month(as.ym(202412), fmt="mm")

AddMonths(201511, 5)

AddMonths(c(201511, 201302), c(5, 15))
AddMonths(c(201511, 201302), c(5, -4))

DescTools documentation built on Sept. 26, 2024, 1:07 a.m.