vector of years. The years should be entered in their full four-digit form; it is assumed that two-digit years refer to the first century.
jul
vector of Julian dates (the number of days since
origin).
OPTIONAL ARGUMENTS:
origin
vector specifying the month, day, and year of the origin. If
origin is missing, it defaults to
options(chron.origin) if this is not NULL, and
c(month=1, day=1, year=1960) otherwise.
VALUE:
When
julian is called, a vector of Julian dates corresponding to the input values is returned.
If
month.day.year is called, a list with members
month,
day, and
year is returned, corresponding to the given Julian dates.
The
leap.year function returns a logical vector indicating whether the input years are leap years.
The
day.of.week function returns a number between 0 and 6 that specifies the day of the week of the given date; 0 refers to Sunday.
These functions are taken from Becker, Chambers, and Wilks (1988), and were slightly modified to include
origin arguments and accept
dates objects.
The original functions are stored in
library(examples).
SEE ALSO:
,
.
EXAMPLES:
# The number of days from January 1, 1990 to each of:
# January 15, 1990
# February 15, 1991
# March 15, 1992
# etc.
n.days <- julian(1:12, rep(15,12), 1990+(0:11), origin=c(1,1,1990))
# November 12, 98, was a Wednesday.
day.of.week(m = 11, d = 12, y = 98)
# November 12, 1998, was a Thursday.
day.of.week(m = 11, d = 12, y = 1998)