stri_datetime_format: Date and Time Formatting and Parsing

Description

These functions convert a given date/time object to a character vector, or vice versa.

Usage

stri_datetime_format(
  time,
  format = "uuuu-MM-dd HH:mm:ss",
  tz = NULL,
  locale = NULL
)

stri_datetime_parse(
  str,
  format = "uuuu-MM-dd HH:mm:ss",
  lenient = FALSE,
  tz = NULL,
  locale = NULL
)

Arguments

time

an object of class POSIXct (as.POSIXct will be called on character vectors and objects of class POSIXlt, Date, and factor)

format

character vector, see Details; see also stri_datetime_fstr

tz

NULL or '' for the default time zone or a single string with a timezone identifier, see stri_timezone_get and stri_timezone_list

locale

NULL or '' for the default locale, or a single string with locale identifier; a non-Gregorian calendar may be specified by setting the @calendar=name keyword

str

character vector

lenient

single logical value; should date/time parsing be lenient?

Details

Vectorized over format and time or str.

By default, stri_datetime_format (for the sake of compatibility with the strftime function) formats a date/time object using the current default time zone.

format may be one of DT_STYLE or DT_relative_STYLE, where DT is equal to date, time, or datetime, and STYLE is equal to full, long, medium, or short. This gives a locale-dependent date and/or time format. Note that currently ICU does not support relative time formats, thus this flag is currently ignored in such a context.

Otherwise, format is a pattern: a string where specific sequences of characters are replaced with date/time data from a calendar when formatting or used to generate data for a calendar when parsing. For example, y stands for ‘year’. Characters may be used multiple times: yy might produce 99, whereas yyyy yields 1999. For most numerical fields, the number of characters specifies the field width. For example, if h is the hour, h might produce 5, but hh yields 05. For some characters, the count specifies whether an abbreviated or full form should be used.

Two single quotes represent a literal single quote, either inside or outside single quotes. Text within single quotes is not interpreted in any way (except for two adjacent single quotes). Otherwise, all ASCII letters from a to z and A to Z are reserved as syntax characters, and require quoting if they are to represent literal characters. In addition, certain ASCII punctuation characters may become available in the future (e.g., : being interpreted as the time separator and / as a date separator, and replaced by respective locale-sensitive characters in display).

Symbol

Meaning

Example(s)

Output

G

era designator

G, GG, or GGG

AD

GGGG

Anno Domini

GGGGG

A

y

year

yy

96

y or yyyy

1996

u

extended year

u

4601

U

cyclic year name, as in Chinese lunar calendar

U

r

related Gregorian year

r

1996

Q

quarter

Q or QQ

02

QQQ

Q2

QQQQ

2nd quarter

QQQQQ

2

q

Stand Alone quarter

q or qq

02

qqq

Q2

qqqq

2nd quarter

qqqqq

2

M

month in year

M or MM

09

MMM

Sep

MMMM

September

MMMMM

S

L

Stand Alone month in year

L or LL

09

LLL

Sep

LLLL

September

LLLLL

S

w

week of year

w or ww

27

W

week of month

W

2

d

day in month

d

2

dd

02

D

day of year

D

189

F

day of week in month

F

2 (2nd Wed in July)

g

modified Julian day

g

2451334

E

day of week

E, EE, or EEE

Tue

EEEE

Tuesday

EEEEE

T

EEEEEE

Tu

e

local day of week

e or ee

2

example: if Monday is 1st day, Tuesday is 2nd )

eee

Tue

eeee

Tuesday

eeeee

T

eeeeee

Tu

c

Stand Alone local day of week

c or cc

2

ccc

Tue

cccc

Tuesday

ccccc

T

cccccc

Tu

a

am/pm marker

a

pm

h

hour in am/pm (1~12)

h

7

hh

07

H

hour in day (0~23)

H

0

HH

00

k

hour in day (1~24)

k

24

kk

24

K

hour in am/pm (0~11)

K

0

KK

00

m

minute in hour

m

4

mm

04

s

second in minute

s

5

ss

05

S

fractional second - truncates (like other time fields)

S

2

to the count of letters when formatting. Appends

SS

23

zeros if more than 3 letters specified. Truncates at

SSS

235

three significant digits when parsing.

SSSS

2350

A

milliseconds in day

A

61201235

z

Time Zone: specific non-location

z, zz, or zzz

PDT

zzzz

Pacific Daylight Time

Z

Time Zone: ISO8601 basic hms? / RFC 822

Z, ZZ, or ZZZ

-0800

Time Zone: long localized GMT (=OOOO)

ZZZZ

GMT-08:00

Time Zone: ISO8601 extended hms? (=XXXXX)

ZZZZZ

-08:00, -07:52:58, Z

O

Time Zone: short localized GMT

O

GMT-8

Time Zone: long localized GMT (=ZZZZ)

OOOO

GMT-08:00

v

Time Zone: generic non-location

v

PT

(falls back first to VVVV)

vvvv

Pacific Time or Los Angeles Time

V

Time Zone: short time zone ID

V

uslax

Time Zone: long time zone ID

VV

America/Los_Angeles

Time Zone: time zone exemplar city

VVV

Los Angeles

Time Zone: generic location (falls back to OOOO)

VVVV

Los Angeles Time

X

Time Zone: ISO8601 basic hm?, with Z for 0

X

-08, +0530, Z

Time Zone: ISO8601 basic hm, with Z

XX

-0800, Z

Time Zone: ISO8601 extended hm, with Z

XXX

-08:00, Z

Time Zone: ISO8601 basic hms?, with Z

XXXX

-0800, -075258, Z

Time Zone: ISO8601 extended hms?, with Z

XXXXX

-08:00, -07:52:58, Z

x

Time Zone: ISO8601 basic hm?, without Z for 0

x

-08, +0530

Time Zone: ISO8601 basic hm, without Z

xx

-0800

Time Zone: ISO8601 extended hm, without Z

xxx

-08:00

Time Zone: ISO8601 basic hms?, without Z

xxxx

-0800, -075258

Time Zone: ISO8601 extended hms?, without Z

xxxxx

-08:00, -07:52:58

escape for text

(nothing)

‘ ‘

two single quotes produce one

‘ ‘

Note that any characters in the pattern that are not in the ranges of [a-z] and [A-Z] will be treated as quoted text. For instance, characters like :, ., (a space), # and @ will appear in the resulting time text even if they are not enclosed within single quotes. The single quote is used to “escape” the letters. Two single quotes in a row, inside or outside a quoted sequence, represent a “real” single quote.

A few examples:

Example Pattern

Result

yyyy.MM.dd ‘at’ HH:mm:ss zzz

2015.12.31 at 23:59:59 GMT+1

EEE, MMM d, ‘’yy

czw., gru 31, ‘15

h:mm a

11:59 PM

hh ‘o’’clock’ a, zzzz

11 o’clock PM, GMT+01:00

K:mm a, z

11:59 PM, GMT+1

yyyyy.MMMM.dd GGG hh:mm aaa

2015.grudnia.31 n.e. 11:59 PM

uuuu-MM-dd’T’HH:mm:ssZ

2015-12-31T23:59:59+0100 (the ISO 8601 guideline)

Value

stri_datetime_format returns a character vector.

stri_datetime_parse returns an object of class POSIXct.

Author(s)

Marek Gagolewski and other contributors

References

Formatting Dates and Times – ICU User Guide, https://unicode-org.github.io/icu/userguide/format_parse/datetime/

Examples

stri_datetime_parse(c('2015-02-28', '2015-02-29'), 'yyyy-MM-dd')
## [1] "2015-02-28 10:33:17 AEDT" NA
stri_datetime_parse(c('2015-02-28', '2015-02-29'), 'yyyy-MM-dd', lenient=TRUE)
## [1] "2015-02-28 10:33:17 AEDT" "2015-03-01 10:33:17 AEDT"
stri_datetime_parse('19 lipca 2015', 'date_long', locale='pl_PL')
## [1] "2015-07-19 10:33:17 AEST"
stri_datetime_format(stri_datetime_now(), 'datetime_relative_medium')
## [1] "today, 10:33:17 am"