Conditionally convert x to yearmon if the conversion is unique, retaining x as names.

Convert x to class "yearmon". If duplicate months are found, return x. Otherwise, return the conversion with names = x.

Usage

as.yearmon2(x, ...)

Arguments

x

object suitable for as.yearmon

...

additional argument(s) (e.g., a format) passed to as.yearmon.

Details

Dates for some monthly data include the day of the month on which the data were published. For many purposes, one would like to have the data as a zoo object with a yearmon index, while still retaining the full date for other purposes.

If the yearmon form of the input is not unique, as.yearmon2 returns the input unchanged with a warning. Otherwise, it returns the yearmon conversion with the input as names.

Value

Returns either its argument or its argument converted to class yearmon with names.

See also

yearmon

Examples

x1 <- as.Date(c("2000-01-01", "2000-01-01"))
as.yearmon2(x1)
#> Warning: 1 duplicate months found in 'x';  returning 'x' unchanged
#> [1] "2000-01-01" "2000-01-01"
#Warning message:
#In as.yearmon2(x1) :
#  1 duplicate months found in 'x';  returning 'x' unchanged

x2 <- as.Date(c("2000-01-01", "2000-02-01"))
as.yearmon2(x2)
#> 2000-01-01 2000-02-01 
#> "Jan 2000" "Feb 2000" 
# month of x2 with names x2