epidate {epitools}R Documentation

Convert dates into multiple legible formats

Description

Convert character vector of dates into multiple legible formats.

Usage

epidate(x, format = "%m/%d/%Y", cal.dates = FALSE,
        before = 7, after = 7, sunday = TRUE)

Arguments

x character vector of dates to be converted
format format of character vector of dates
cal.dates Calendar dates that contains x, starting 7 days 'before' (default) until 7 days 'after' x
before defines lower limit of cal.dates: default is 7 days before earliest date in x
after defines upper limit of cal.dates: default is 7 days after latest date in x
sunday first day of the week is either Sunday (default) or Monday

Details

Dates can come in many formats (e.g., November 12, 2001, 12Nov01, 11/12/2001, 11/12/01, 2001-11-12) and need to be converted into other formats for data analysis, graphical displays, generating reports, etc.

There is tremendous flexibility in converting any character vector with sufficient information to be converted into a unique date. For complete options for the format option see strptime.

Value

dates dates wtih date-time class
julian number of days since 1970-01-01
mday day of the month: 1-31
mon month of the year: 0-11
month month: January, February, March, ...
month2 month: Jan, Feb, Mar, ...
firstday first day of the week: Sunday or Monday
week week of the year: 0-53
year year: YYYY
yr year: YY
wday day of the week: 0-6
weekday weekday: Monday, Tuesday, Wednesday, ...
wkday weekday: Mon, Tue, Wed, ...
yday day of the year: 0-365
quarter quarter of the year: Q1, Q2, Q3, Q4
cdates Calendar dates that contains dates
cjulian Julian calendar dates

Note

Visit http://www.epitools.net for the latest.

Author(s)

Tomas Aragon, aragon@berkeley.edu, http://www.medepi.com

References

none

See Also

epitools: as.week

DateTimeClasses to learn about date-time classes

as.Date to convert character vector of dates into calendar dates with date-time class (done by epidate)

strptime to convert date-time character strings into a date-time class

format.POSIXlt or format.POSIXlt to convert date-time classes into character representations

as.POSIXlt to convert either date-time objects or date-time character strings into a human legible date-time class (done by epidate)

as.POSIXct to convert either date-time objects or date-time character strings into a continuous time date-time class (not done by epidate)

weekdays, months, quarters, or julian, to convert date-time objects into weekdays, months, quarters, or julian representations, respectively (all are done by epidate)

Examples

#x <- c("12/1/03", "11/2/03", NA, "1/7/04", "1/14/04", "8/18/04")
#epidate(x, format = "%m/%d/%y")
#epidate(x, format = "%m/%d/%y", TRUE)
#
###convert vector of disease weeks into vector of mid-week dates
#dwk <- sample(0:53, 100, replace = TRUE)
#wk2date <- paste(dwk, "/", "Wed", sep="")
#wk2date[1:10]
#wk2date2 <- epidate(wk2date, format = "%U/%a")
#wk2date2$dates[1:20]

[Package epitools version 0.5-3 Index]