| Title: | Recognize and Parse Dates in Various Formats, Including All ISO 8601 Formats |
|---|---|
| Description: | Parse dates automatically, without the need of specifying a format. Currently it includes the git date parser. It can also recognize and parse all ISO 8601 formats. |
| Authors: | Gábor Csárdi, Linus Torvalds |
| Maintainer: | Gábor Csárdi <[email protected]> |
| License: | GPL-2 |
| Version: | 1.3.1.9000 |
| Built: | 2024-06-09 04:10:12 UTC |
| Source: | https://github.com/gaborcsardi/parsedate |
Three useful functions to parse and format dates.
parse_iso_8601 recognizes and parses all valid ISO
8601 date and time formats. It can also be used as an ISO 8601
validator.
parse_date can parse a date when you don't know
which format it is in. First it tries all ISO 8601 formats.
Then it tries git's versatile date parser. Lastly, it tries
as.POSIXct.
format_iso_8601 formats a date (and time) in
a specific ISO 8601 format.
Format a date in a fixed format that is ISO 8601 valid, and can be used to compare dates as character strings. It converts the date(s) to UTC.
format_iso_8601(date)format_iso_8601(date)
date |
The date(s) to format. |
Character vector of formatted dates.
format_iso_8601(parse_iso_8601("2013-02-08")) format_iso_8601(parse_iso_8601("2013-02-08 09:34:00")) format_iso_8601(parse_iso_8601("2013-02-08 09:34:00+01:00")) format_iso_8601(parse_iso_8601("2013-W06-5")) format_iso_8601(parse_iso_8601("2013-039"))format_iso_8601(parse_iso_8601("2013-02-08")) format_iso_8601(parse_iso_8601("2013-02-08 09:34:00")) format_iso_8601(parse_iso_8601("2013-02-08 09:34:00+01:00")) format_iso_8601(parse_iso_8601("2013-W06-5")) format_iso_8601(parse_iso_8601("2013-039"))
Recognize and parse dates from a wide range of formats. The current algorithm is the following:
Try parsing dates using all valid ISO 8601 formats, by
calling parse_iso_8601.
If this fails, then try parsing them using the git date parser.
If this fails, then try parsing them using as.POSIXct.
(It is unlikely that this step will parse any dates that the
first two steps couldn't, but it is still a logical fallback,
to make sure that we can parse at least as many dates as
as.POSIXct.
parse_date returns quickly in case of empty input elements.
parse_date(dates, approx = TRUE, default_tz = "UTC")parse_date(dates, approx = TRUE, default_tz = "UTC")
dates |
A character vector. An error is reported if the function cannot coerce this parameter to a character vector. |
approx |
Logical flag, whether the git parse should try
hard(er). If this is set to |
default_tz |
Time zone to assume for dates that don't specify a time zone explicitly. Defaults to UTC, and an empty string means the local time zone. |
All dates are returned in the UTC time zone. If you prefer a different time zone, simply use '.POSIXct()' on the result, see examples below.
A POSIXct vector. NA is returned for
the dates that parse_date could not parse.
# Some easy examples parse_date("2014-12-12") parse_date("04/15/99") parse_date("15/04/99") # Ambiguous format, parsed assuming MM/DD/YY parse_date("12/11/99") parse_date("11/12/99") # Fill in the current date and time parse_date("03/20") parse_date("12") # But not for this, because this is ISO 8601 parse_date("2014") # Handle vectors and empty input parse_date(c("2014","2015","","2016")) # Convert result to local time tz <- format(Sys.time(), "%Z") as.POSIXct(parse_date("2014-12-13T11:12:13"), tz) # Local time zone parse_date("2014-12-13T11:12:13", default_tz = "CET") parse_date("2014-12-13T11:12:13", default_tz = "UTC") # Convert results to different timezone parse_date("2015-12-13T11:12:13") .POSIXct(parse_date("2015-12-13T11:12:13"), tz = "CET")# Some easy examples parse_date("2014-12-12") parse_date("04/15/99") parse_date("15/04/99") # Ambiguous format, parsed assuming MM/DD/YY parse_date("12/11/99") parse_date("11/12/99") # Fill in the current date and time parse_date("03/20") parse_date("12") # But not for this, because this is ISO 8601 parse_date("2014") # Handle vectors and empty input parse_date(c("2014","2015","","2016")) # Convert result to local time tz <- format(Sys.time(), "%Z") as.POSIXct(parse_date("2014-12-13T11:12:13"), tz) # Local time zone parse_date("2014-12-13T11:12:13", default_tz = "CET") parse_date("2014-12-13T11:12:13", default_tz = "UTC") # Convert results to different timezone parse_date("2015-12-13T11:12:13") .POSIXct(parse_date("2015-12-13T11:12:13"), tz = "CET")
See https://en.wikipedia.org/wiki/ISO_8601 and links therein for the complete standard.
parse_iso_8601(dates, default_tz = "UTC")parse_iso_8601(dates, default_tz = "UTC")
dates |
A character vector. An error is reported if the function cannot coerce this parameter to a character vector. |
default_tz |
Time zone to assume for dates that don't specify a time zone explicitly. Defaults to UTC, and an empty string means the local time zone. |
A POSIXct vector. NA is returned for
the dates that parse_date could not parse.
# Missing fields parse_iso_8601("2013-02-08 09") parse_iso_8601("2013-02-08 09:30") # Separator between date and time can be a 'T' parse_iso_8601("2013-02-08T09") parse_iso_8601("2013-02-08T09:30") parse_iso_8601("2013-02-08T09:30:26") # Fractional seconds, minutes, hours parse_iso_8601("2013-02-08T09:30:26.123") parse_iso_8601("2013-02-08T09:30.5") parse_iso_8601("2013-02-08T09,25") # Zulu time zone is UTC parse_iso_8601("2013-02-08T09:30:26Z") # ISO weeks, not very intuitive parse_iso_8601("2013-W06-5") parse_iso_8601("2013-W01-1") parse_iso_8601("2009-W01-1") parse_iso_8601("2009-W53-7") # Day of the year parse_iso_8601("2013-039") parse_iso_8601("2013-039 09:30:26Z")# Missing fields parse_iso_8601("2013-02-08 09") parse_iso_8601("2013-02-08 09:30") # Separator between date and time can be a 'T' parse_iso_8601("2013-02-08T09") parse_iso_8601("2013-02-08T09:30") parse_iso_8601("2013-02-08T09:30:26") # Fractional seconds, minutes, hours parse_iso_8601("2013-02-08T09:30:26.123") parse_iso_8601("2013-02-08T09:30.5") parse_iso_8601("2013-02-08T09,25") # Zulu time zone is UTC parse_iso_8601("2013-02-08T09:30:26Z") # ISO weeks, not very intuitive parse_iso_8601("2013-W06-5") parse_iso_8601("2013-W01-1") parse_iso_8601("2009-W01-1") parse_iso_8601("2009-W53-7") # Day of the year parse_iso_8601("2013-039") parse_iso_8601("2013-039 09:30:26Z")