Parse date/times
parse_datetime(x, format = "", na = c("", "NA"), locale = default_locale(), trim_ws = TRUE) parse_date(x, format = "", na = c("", "NA"), locale = default_locale(), trim_ws = TRUE) parse_time(x, format = "", na = c("", "NA"), locale = default_locale(), trim_ws = TRUE) col_datetime(format = "") col_date(format = "") col_time(format = "")
| x | A character vector of dates to parse. |
|---|---|
| format | A format specification, as described below. If set to "",
date times are parsed as ISO8601, dates and times used the date and
time formats specified in the Unlike |
| na | Character vector of strings to interpret as missing values. Set this
option to |
| locale | The locale controls defaults that vary from place to place.
The default locale is US-centric (like R), but you can use
|
| trim_ws | Should leading and trailing whitespace be trimmed from each field before parsing it? |
A POSIXct() vector with tzone attribute set to
tz. Elements that could not be parsed (or did not generate valid
dates) will be set to NA, and a warning message will inform
you of the total number of failures.
readr uses a format specification similar to strptime().
There are three types of element:
Date components are specified with "%" followed by a letter.
For example "%Y" matches a 4 digit year, "%m", matches a 2 digit
month and "%d" matches a 2 digit day. Month and day default to 1,
(i.e. Jan 1st) if not present, for example if only a year is given.
Whitespace is any sequence of zero or more whitespace characters.
Any other character is matched exactly.
parse_datetime() recognises the following format specifications:
Year: "%Y" (4 digits). "%y" (2 digits); 00-69 -> 2000-2069, 70-99 -> 1970-1999.
Month: "%m" (2 digits), "%b" (abbreviated name in current locale), "%B" (full name in current locale).
Day: "%d" (2 digits), "%e" (optional leading space), "
Hour: "%H" or "%I", use I (and not H) with AM/PM.
Minutes: "%M"
Seconds: "%S" (integer seconds), "%OS" (partial seconds)
Time zone: "%Z" (as name, e.g. "America/Chicago"), "%z" (as offset from UTC, e.g. "+0800")
AM/PM indicator: "%p".
Non-digits: "%." skips one non-digit character, "%+" skips one or more non-digit characters, "%*" skips any number of non-digits characters.
Automatic parsers: "%AD" parses with a flexible YMD parser, "%AT" parses with a flexible HMS parser.
Shortcuts: "%D" = "%m/%d/%y", "%F" = "%Y-%m-%d", "%R" = "%H:%M", "%T" = "%H:%M:%S", "%x" = "%y/%m/%d".
Currently, readr does not support all of ISO8601. Missing features:
Week & weekday specifications, e.g. "2013-W05", "2013-W05-10"
Ordinal dates, e.g. "2013-095".
Using commas instead of a period for decimal separator
The parser is also a little laxer than ISO8601:
Dates and times can be separated with a space, not just T.
Mostly correct specifications like "2009-05-19 14:" and "200912-01" work.
Other parsers: col_skip,
cols_condense, cols,
parse_factor, parse_guess,
parse_logical, parse_number,
parse_vector
# Format strings -------------------------------------------------------- parse_datetime("01/02/2010", "%d/%m/%Y")#> [1] "2010-02-01 UTC"parse_datetime("01/02/2010", "%m/%d/%Y")#> [1] "2010-01-02 UTC"# Handle any separator parse_datetime("01/02/2010", "%m%.%d%.%Y")#> [1] "2010-01-02 UTC"# Dates look the same, but internally they use the number of days since # 1970-01-01 instead of the number of seconds. This avoids a whole lot # of troubles related to time zones, so use if you can. parse_date("01/02/2010", "%d/%m/%Y")#> [1] "2010-02-01"parse_date("01/02/2010", "%m/%d/%Y")#> [1] "2010-01-02"# You can parse timezones from strings (as listed in OlsonNames()) parse_datetime("2010/01/01 12:00 US/Central", "%Y/%m/%d %H:%M %Z")#> [1] "2010-01-01 18:00:00 UTC"# Or from offsets parse_datetime("2010/01/01 12:00 -0600", "%Y/%m/%d %H:%M %z")#> [1] "2010-01-01 18:00:00 UTC"# Use the locale parameter to control the default time zone # (but note UTC is considerably faster than other options) parse_datetime("2010/01/01 12:00", "%Y/%m/%d %H:%M", locale = locale(tz = "US/Central"))#> [1] "2010-01-01 12:00:00 CST"#> [1] "2010-01-01 12:00:00 EST"# Unlike strptime, the format specification must match the complete # string (ignoring leading and trailing whitespace). This avoids common # errors: strptime("01/02/2010", "%d/%m/%y")#> [1] "2020-02-01 UTC"parse_datetime("01/02/2010", "%d/%m/%y")#> Warning: 1 parsing failure. #> row col expected actual #> 1 -- date like %d/%m/%y 01/02/2010#> [1] NA# Failures ------------------------------------------------------------- parse_datetime("01/01/2010", "%d/%m/%Y")#> [1] "2010-01-01 UTC"#> Warning: 2 parsing failures. #> row col expected actual #> 1 -- date like %d/%m/%Y 01/ab/2010 #> 2 -- valid date 32/01/2010#> [1] NA NA# Locales -------------------------------------------------------------- # By default, readr expects English date/times, but that's easy to change' parse_datetime("1 janvier 2015", "%d %B %Y", locale = locale("fr"))#> [1] "2015-01-01 UTC"#> [1] "2015-01-01 UTC"# ISO8601 -------------------------------------------------------------- # With separators parse_datetime("1979-10-14")#> [1] "1979-10-14 UTC"parse_datetime("1979-10-14T10")#> [1] "1979-10-14 10:00:00 UTC"parse_datetime("1979-10-14T10:11")#> [1] "1979-10-14 10:11:00 UTC"parse_datetime("1979-10-14T10:11:12")#> [1] "1979-10-14 10:11:12 UTC"parse_datetime("1979-10-14T10:11:12.12345")#> [1] "1979-10-14 10:11:12 UTC"# Without separators parse_datetime("19791014")#> [1] "1979-10-14 UTC"parse_datetime("19791014T101112")#> [1] "1979-10-14 10:11:12 UTC"# Time zones us_central <- locale(tz = "US/Central") parse_datetime("1979-10-14T1010", locale = us_central)#> [1] "1979-10-14 10:10:00 CDT"parse_datetime("1979-10-14T1010-0500", locale = us_central)#> [1] "1979-10-14 10:10:00 CDT"parse_datetime("1979-10-14T1010Z", locale = us_central)#> [1] "1979-10-14 05:10:00 CDT"#> [1] "1979-10-14 10:10:00 UTC"