ID EN
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Date & Time

weekdays

R Base 3.6.2

Extract the weekday, month or quarter, or the Julian time (days since some origin). These are generic functions: the methods for the internal date-time classes are documented here.

Syntax

R 
weekdays(x, abbreviate)
# S3 method for POSIXt
weekdays(x, abbreviate = FALSE)
# S3 method for Date
weekdays(x, abbreviate = FALSE)<p></p><p>months(x, abbreviate)
# S3 method for POSIXt
months(x, abbreviate = FALSE)
# S3 method for Date
months(x, abbreviate = FALSE)</p><p>quarters(x, abbreviate)
# S3 method for POSIXt
quarters(x, &#8230;)
# S3 method for Date
quarters(x, &#8230;)</p><p>julian(x, &#8230;)
# S3 method for POSIXt
julian(x, origin = as.POSIXct("1970-01-01", tz = "GMT"), &#8230;)
# S3 method for Date
julian(x, origin = as.Date("1970-01-01"), &#8230;)</p>

Arguments

Parameter Description
x an object inheriting from class "POSIXt" or "Date".
abbreviate logical vector (possibly recycled). Should the names be abbreviated?
origin an length-one object inheriting from class "POSIXt" or "Date".
&#8230; arguments for other methods.

Return Value

weekdays and months return a character vector of names in the locale in use. quarters returns a character vector of "Q1" to "Q4". julian returns the number of days (possibly fractional) since the origin, with the origin as a "origin" attribute. All time calculations in R are done ignoring leap-seconds.

Examples

Example
R 
# NOT RUN {
weekdays(.leap.seconds)
months(.leap.seconds)
quarters(.leap.seconds)

## Julian Day Number (JDN, https://en.wikipedia.org/wiki/Julian_day)
## is the number of days since noon UTC on the first day of 4317 BC.
## in the proleptic Julian calendar.  To more recently, in
## 'Terrestrial Time' which differs from UTC by a few seconds
## See https://en.wikipedia.org/wiki/Terrestrial_Time
julian(Sys.Date(), -2440588) # from a day
floor(as.numeric(julian(Sys.time())) + 2440587.5) # from a date-time
# }

See Also

DateTimeClasses Date