baseDay function

Base Day

Computes the base day of the year, a reference value that can be used to group days for the computation of summary statistics. From smwrBase package.

baseDay(x, numeric = TRUE, year = c("calendar", "water", "climate"))

Arguments

• x: a vector of class POSIXt, Dates, or character that represents a date. Missing values are permitted.
• numeric: a logical value; TRUE means return the numeric value of the day, FALSE means return a factor.
• year: a character string indicating the basis of the factor levels. See Details .

Returns

An integer value representing the base day number if numeric

is TRUE. Otherwise a factor with levels for every day of the year.

Details

The base day is computed such that all dates have the same reference value regardless of whether the year is a leap year or not. If year is "calendar," then the factor levels or day number begin on January 1; if year is "water," then the factor levels or day number begin on October 1; and if year is "climate," then the factor levels or day number begin on April 1.

Examples

# The default numeric result
baseDay(c("2000-02-29", "2000-03-01", "2001-03-01"))
# The result as a factor
baseDay(c("2000-02-29", "2000-03-01", "2001-03-01"), numeric=FALSE)