Basic Date Functions
Some more date functions for making daily life a bit easier. The first ones extract a specific part of a given date, others check some conditions.
Year(x)
Quarter(x)
Month(x, fmt = c("m", "mm", "mmm"), lang = DescToolsOptions("lang"),
stringsAsFactors = TRUE)
Week(x, method = c("iso", "us"))
Day(x)
Weekday(x, fmt = c("d", "dd", "ddd"), lang = DescToolsOptions("lang"),
stringsAsFactors = TRUE)
YearDay(x)
YearMonth(x)
Day(x) <- value
IsWeekend(x)
IsLeapYear(x)
Hour(x)
Minute(x)
Second(x)
Timezone(x)
Now()
Today()
DiffDays360(start_d, end_d, method = c("eu", "us"))
LastDayOfMonth(x)
YearDays(x)
MonthDays(x)x |
the date to be evaluated. |
fmt |
format string, defines how the month or the weekday are to be formatted. Defaults to |
value |
new value |
lang |
optional value setting the language for the months and daynames. Can be either |
stringsAsFactors |
logical. Defines if the result should be coerced to a factor, using the local definitions as levels. The result would be an ordered factor. Default is TRUE. |
start_d, end_d |
the start, resp. end date for |
method |
one out of |
These functions are mainly convenience wrappers for the painful format() and its strange codes...
Based on the requested time component, the output is as follows:Year returns the year of the input date in yyyy format.Quarter returns the quarter of the year (1 to 4) for the input date. Month returns the month of the year (1 to 12) for the input date. Week returns the week of the year for the input date (0 to 53), as defined in ISO8601. Weekday returns the week day of the input date. (1 - Monday, 2 - Tuesday, ... 7 - Sunday). (Names and abbreviations are either english or in the current locale!)YearDay returns the day of the year numbering (1 to 366). Day returns the day of the month (1 to 31). YearMonth returns the yearmonth representation (yyyymm) of a date as long integer. Hour, Minute, Second, Timezone return the hour, minute, second or timezone from a POSIXlt object. Today, Now return the current date, resp. the current date and time.
IsWeekend returns TRUE, if the date x falls on a weekend. IsLeapYear returns TRUE, if the year of the date x is a leap year.
The day can not only be extracted, but as well be defined. See examples.
DiffDays360 calculates the difference between 2 dates using the 360-days convention.LastDayOfMonth returns the last day of the month of the given date(s).
YearDays returns the total number of days of the given date(s).
MonthDays returns the numer of days of the month of the given date(s).
The language in Weekday and Moth can be set with an option as well. The functions will check for an existing option named "lang" and take this value if it exists. So simply set option(lang="engl") if the results should always be reported in English.
a vector of the same dimension as x, consisting of either numeric values or characters depending on the function used.
Andri Signorell <andri@signorell.net>
x <- Today() # the same as Sys.Date() but maybe easier to remember..
Year(x)
Quarter(x)
Month(x)
Month(x, fmt = "mm", lang="engl")
Month(x, fmt = "mm", lang="local")
Month(x, fmt = "mmm", lang="engl")
Month(x, fmt = "mmm", lang="local")
Week(x)
Day(x)
Day(x) <- 20
x
Weekday(x)
Weekday(x, fmt = "dd", lang="engl")
Weekday(x, fmt = "dd", lang="local")
Weekday(x, fmt = "ddd", lang="engl")
Weekday(x, fmt = "ddd", lang="local")
YearDay(x)
IsWeekend(x)
IsLeapYear(x)
# let's generate a time sequence by weeks
Month(seq(from=as.Date(Sys.Date()), to=Sys.Date()+150, by="weeks"), fmt="mm")
LastDayOfMonth(as.Date(c("2014-10-12","2013-01-31","2011-12-05")))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.