day.of.week {chron} | R Documentation |
Utility functions to convert between Julian dates (numbers of days since an origin, by default 1970-01-01) and calendar dates given by year, month, and day within the month.
## Default S3 method: julian(x, d, y, origin., ...) month.day.year(jul, origin.) leap.year(y) day.of.week(month, day, year)
x, month |
vector of month numbers. |
d, day |
vector of day numbers. |
y, year |
vector of years. |
jul |
vector of Julian Dates, i.e., number of days since
origin. . |
origin. |
vector specifying the origin as month, day, and year.
If missing, it defaults to getOption("chron.origin") if this
is non-null, otherwise
c(month = 1, day = 1, year = 1970) . |
... |
further arguments to be passed to or from methods. |
A vector of Julian dates (number of days since origin.
) when
julian()
is called, or a list with members month
,
day
, year
corresponding to the input Julian dates if
month.day.year()
is called. leap.year()
returns a
logical vector indicating whether the corresponding year is a leap
year.
day.of.week()
returns a number between 0 and 6 to specify day
of the week–0 refers to Sunday.
These functions were taken from Becker, Chambers, and Wilks (1988),
and were slightly modified to take chron
and dates
objects; some also take the extra argument origin.
.
julian(1, 1, 1970) # [1] 0 unlist(month.day.year(0)) # month day year # 1 1 1970