weekdays

0th

Percentile

Extract Parts of a POSIXt or Date Object

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.

Keywords
chron
Usage
weekdays(x, abbreviate)
## S3 method for class 'POSIXt':
weekdays(x, abbreviate = FALSE)
## S3 method for class 'Date':
weekdays(x, abbreviate = FALSE)

months(x, abbreviate) ## S3 method for class 'POSIXt': months(x, abbreviate = FALSE) ## S3 method for class 'Date': months(x, abbreviate = FALSE)

quarters(x, abbreviate) ## S3 method for class 'POSIXt': quarters(x, \dots) ## S3 method for class 'Date': quarters(x, \dots)

julian(x, ...) ## S3 method for class 'POSIXt': julian(x, origin = as.POSIXct("1970-01-01", tz = "GMT"), ...) ## S3 method for class 'Date': julian(x, origin = as.Date("1970-01-01"), ...)

Arguments
x
an object inheriting from class "POSIXt" or "Date".
abbreviate
logical. Should the names be abbreviated?
origin
an length-one object inheriting from class "POSIXt" or "Date".
...
arguments for other methods.
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 Rare done ignoring leap-seconds.

Note

Other components such as the day of the month or the year are very easy to compute: just use as.POSIXlt and extract the relevant component. Alternatively (especially if the components are desired as character strings), use strftime.

See Also

DateTimeClasses, Date

Aliases
  • weekdays
  • weekdays.POSIXt
  • weekdays.Date
  • months
  • months.POSIXt
  • months.Date
  • quarters
  • quarters.POSIXt
  • quarters.Date
  • julian
  • julian.POSIXt
  • julian.Date
Examples
library(base) 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
Documentation reproduced from package base, version 3.3, License: Part of R @VERSION@

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