Date3to1: Convert three YMD vectors to a Date

Description

Given a data.frame with 3 columns, assume they represent Year, Month and Day and return a vector of class "Date".

Usage

Date3to1(data, default='Start')

Arguments

data

a data.frame with 3 columns assumed to represent Year, Month and Day.

default

A character string to indicate how missing months and days should be treated. If the first letter is "S" or "s", the default month will be 1 and the default day will be 1. Otherwise, "End" is assumed, for which the default month will be 12 and the default day will be the last day of the month.

NOTE: Any number outside the range of 1 to the last day of the month is considered missing and its subscript is noted in the optional attribute "missing".

Value

Returns an object of class "Date" with an optional attribute "missing" giving the indices of any elements with missing months or days, for which a default month or day was supplied.

Details

The data sets from the Correlates of War project include dates coded in triples of columns with names like c("StartMonth1", "StartDay1", "StartYear1", "EndMonth1", ..., "EndYear2"). This function will accept one triple and translate it into a vector of class "Date".

Examples

Run this code

# NOT RUN {
date.frame <- data.frame(Year=c(NA, -1, 1971:1979), 
      Month=c(1:2, -1, NA, 13, 2, 12, 6:9), 
      Day=c(0, 0:6, NA, -1, 32) )
     
DateVecS <- Date3to1(date.frame)
DateVecE <- Date3to1(date.frame, "End")
                         
# check 
na <- c(1:5, 9:11)
DateVs <- as.Date(c(NA, NA, 
  '1971-01-01', '1972-01-01', '1973-01-01', 
  '1974-02-04', '1975-12-05', '1976-06-06', 
  '1977-07-01', '1978-08-01', '1979-09-01') ) 
DateVe <- as.Date(c(NA, NA, 
  '1971-12-31', '1972-12-31', '1973-12-31', 
  '1974-02-04', '1975-12-05', '1976-06-06', 
  '1977-07-31', '1978-08-31', '1979-09-30') ) 

attr(DateVs, 'missing') <- na
attr(DateVe, 'missing') <- na

# }
# NOT RUN {
all.equal(DateVecS, DateVs)
# }
# NOT RUN {
all.equal(DateVecE, DateVe)
# }