R: Add a Month to a Date

AddMonths {DescTools} | R Documentation

## Add a Month to a Date

### Description

Clueless adding numbers of months to a date will in some cases lead to invalid dates, think of e.g. 2012-01-30 + 1 month.
AddMonths ensures that the result is always a valid date, e.g. `as.Date("2013-01-31") + 1 month` will be `"2013-02-28"`. If number `n` is negative, the months will be subtracted.

### Usage

    AddMonths(x, n, ...)

### Arguments

`x` | a Date object (or something which can be coerced by `as.Date`(x, ...) to such an object) to which a number of months has to be added.
`n` | the number of months to be added. If n is negative the months will be subtracted.
`...` | the dots are passed to `as.Date`, e.g. for supplying `origin`.

### Details

All parameters will be recyled if necessary.

### Value

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

### Author(s)

Andri Signorell <andri@signorell.net>, based on code by Roland Rapold and Antonio

### References

Thanks to Antonio: http://stackoverflow.com/questions/14169620/add-a-month-to-a-date

### See Also

`AddMonthsYM`; Date functions: `Year`, `Month`, etc.

### Examples

    # characters will be coerced to Date
    AddMonths("2013-01-31", 1)

    # negative n
    AddMonths(as.Date("2013-03-31"), -1)

    # Arguments will be recycled
    # (with warning if the longer is not a multiple of length of shorter)
    AddMonths(c("2013-01-31", "2013-03-31", "2013-10-31", "2013-12-31"), c(1,-1))

    x <- as.POSIXct(c("2015-01-31", "2015-08-31"))
    n <- c(1, 3)
    AddMonths(x, n)

    # mind the origin if x supplied as numeric ...
    x <- as.numeric(as.Date(x))
    AddMonths(x, n, origin=as.Date("1970-01-01"))

[Package DescTools version 0.99.26 Index]