lubridate (version 1.3.0)

ymd_hms: Parse dates that have hours, minutes, or seconds elements.

Description

Transform dates stored as character or numeric vectors to POSIXct objects. ymd_hms family of functions recognize all non-alphanumeric separators (with the exception of "." if frac = TRUE) and correctly handle heterogeneous date-time representations. For more flexibility in treatment of heterogeneous formats, see low level parser parse_date_time.

Usage

ymd_hms(..., quiet = FALSE, tz = "UTC",
    locale = Sys.getlocale("LC_TIME"), truncated = 0)

Arguments

...

a character vector of dates in year, month, day, hour, minute, second format

quiet

logical. When TRUE function evalueates without displaying customary messages.

tz

a character string that specifies which time zone to parse the date with. The string must be a time zone that is recognized by the user's OS.

locale

locale to be used, see locales. On linux systems you can use system("locale -a") to list all the installed locales.

truncated

integer, indicating how many formats can be missing. See details.

Value

• a vector of POSIXct date-time objects

Details

ymd_hms() functions automatically assigns the Universal Coordinated Time Zone (UTC) to the parsed date. This time zone can be changed with force_tz.

The most common type of irregularity in date-time data is the truncation due to rounding or unavailability of the time stamp. If truncated parameter is non-zero ymd_hms functions also check for truncated formats. For example ymd_hms with truncated = 3 will also parse incomplete dates like 2012-06-01 12:23, 2012-06-01 12 and 2012-06-01. NOTE: ymd family of functions are based on strptime which currently fails to parse %y-%m formats.

As of version 1.3.0, lubridate's parse functions no longer return a message that displays which format they used to parse their input. You can change this by setting the lubridate.verbose option to true with options(lubridate.verbose = TRUE).

See Also

ymd, hms. parse_date_time for underlying mechanism.

Examples

x <- c("2010-04-14-04-35-59", "2010-04-01-12-00-00")
ymd_hms(x)
# [1] "2010-04-14 04:35:59 UTC" "2010-04-01 12:00:00 UTC"
x <- c("2011-12-31 12:59:59", "2010-01-01 12:00:00")
ymd_hms(x)
# [1] "2011-12-31 12:59:59 UTC" "2010-01-01 12:00:00 UTC"


## ** heterogenuous formats **
x <- c(20100101120101, "2009-01-02 12-01-02", "2009.01.03 12:01:03",
       "2009-1-4 12-1-4",
       "2009-1, 5 12:1, 5",
       "200901-08 1201-08",
       "2009 arbitrary 1 non-decimal 6 chars 12 in between 1 !!! 6",
       "OR collapsed formats: 20090107 120107 (as long as prefixed with zeros)",
       "Automatic wday, Thu, detection, 10-01-10 10:01:10 and p format: AM",
       "Created on 10-01-11 at 10:01:11 PM")
ymd_hms(x)

## ** fractional seconds **
op <- options(digits.secs=3)
dmy_hms("20/2/06 11:16:16.683")
## "2006-02-20 11:16:16.683 UTC"
options(op)

## ** different formats for ISO8601 timezone offset **
ymd_hms(c("2013-01-24 19:39:07.880-0600",
"2013-01-24 19:39:07.880", "2013-01-24 19:39:07.880-06:00",
"2013-01-24 19:39:07.880-06", "2013-01-24 19:39:07.880Z"))

## ** internationalization **
x_RO <- "Ma 2012 august 14 11:28:30 "
ymd_hms(x_RO, locale = "ro_RO.utf8")

## ** truncated time-dates **
x <- c("2011-12-31 12:59:59", "2010-01-01 12:11", "2010-01-01 12", "2010-01-01")
ymd_hms(x, truncated = 3)
##"2011-12-31 12:59:59 UTC" "2010-01-01 12:11:00 UTC" "2010-01-01 12:00:00 UTC" "2010-01-01 00:00:00 UTC"
x <- c("2011-12-31 12:59", "2010-01-01 12", "2010-01-01")
ymd_hm(x, truncated = 2)
## "2011-12-31 12:59:00 UTC" "2010-01-01 12:00:00 UTC" "2010-01-01 00:00:00 UTC"

## ** What lubridate might not handle **
## Extremely weird cases when one of the separators is "" and some of the
## formats are not in double digits might not be parsed correctly:
ymd_hm("20100201 07-01", "20100201 07-1", "20100201 7-01")
## "2010-02-01 07:01:00 UTC" "2010-02-01 07:01:00 UTC"   NA