Arrow: Better dates & times for Python¶

Release v1.2.3 (Installation) (Changelog)

Arrow is a Python library that offers a sensible and human-friendly approach to creating, manipulating, formatting and converting dates, times and timestamps. It implements and updates the datetime type, plugging gaps in functionality and providing an intelligent module API that supports many common creation scenarios. Simply put, it helps you work with dates and times with fewer imports and a lot less code.

Arrow is named after the arrow of time and is heavily inspired by moment.js and requests.

Why use Arrow over built-in modules?¶

Python’s standard library and some other low-level modules have near-complete date, time and timezone functionality, but don’t work very well from a usability perspective:

Too many modules: datetime, time, calendar, dateutil, pytz and more
Too many types: date, time, datetime, tzinfo, timedelta, relativedelta, etc.
Timezones and timestamp conversions are verbose and unpleasant
Timezone naivety is the norm
Gaps in functionality: ISO 8601 parsing, timespans, humanization

Features¶

Fully-implemented, drop-in replacement for datetime
Support for Python 3.6+
Timezone-aware and UTC by default
Super-simple creation options for many common input scenarios
shift method with support for relative offsets, including weeks
Format and parse strings automatically
Wide support for the ISO 8601 standard
Timezone conversion
Support for dateutil, pytz, and ZoneInfo tzinfo objects
Generates time spans, ranges, floors and ceilings for time frames ranging from microsecond to year
Humanize dates and times with a growing list of contributed locales
Extensible for your own Arrow-derived types
Full support for PEP 484-style type hints

Quick Start¶

Installation¶

To install Arrow, use pip or pipenv:

$ pip install -U arrow

Example Usage¶

>>> import arrow
>>> arrow.get('2013-05-11T21:23:58.970460+07:00')
<Arrow [2013-05-11T21:23:58.970460+07:00]>

>>> utc = arrow.utcnow()
>>> utc
<Arrow [2013-05-11T21:23:58.970460+00:00]>

>>> utc = utc.shift(hours=-1)
>>> utc
<Arrow [2013-05-11T20:23:58.970460+00:00]>

>>> local = utc.to('US/Pacific')
>>> local
<Arrow [2013-05-11T13:23:58.970460-07:00]>

>>> local.timestamp()
1368303838.970460

>>> local.format()
'2013-05-11 13:23:58 -07:00'

>>> local.format('YYYY-MM-DD HH:mm:ss ZZ')
'2013-05-11 13:23:58 -07:00'

>>> local.humanize()
'an hour ago'

>>> local.humanize(locale='ko-kr')
'한시간 전'

User’s Guide¶

Creation¶

Get ‘now’ easily:

>>> arrow.utcnow()
<Arrow [2013-05-07T04:20:39.369271+00:00]>

>>> arrow.now()
<Arrow [2013-05-06T21:20:40.841085-07:00]>

>>> arrow.now('US/Pacific')
<Arrow [2013-05-06T21:20:44.761511-07:00]>

Create from timestamps (int or float):

>>> arrow.get(1367900664)
<Arrow [2013-05-07T04:24:24+00:00]>

>>> arrow.get(1367900664.152325)
<Arrow [2013-05-07T04:24:24.152325+00:00]>

Use a naive or timezone-aware datetime, or flexibly specify a timezone:

>>> arrow.get(datetime.utcnow())
<Arrow [2013-05-07T04:24:24.152325+00:00]>

>>> arrow.get(datetime(2013, 5, 5), 'US/Pacific')
<Arrow [2013-05-05T00:00:00-07:00]>

>>> from dateutil import tz
>>> arrow.get(datetime(2013, 5, 5), tz.gettz('US/Pacific'))
<Arrow [2013-05-05T00:00:00-07:00]>

>>> arrow.get(datetime.now(tz.gettz('US/Pacific')))
<Arrow [2013-05-06T21:24:49.552236-07:00]>

Parse from a string:

>>> arrow.get('2013-05-05 12:30:45', 'YYYY-MM-DD HH:mm:ss')
<Arrow [2013-05-05T12:30:45+00:00]>

Search a date in a string:

>>> arrow.get('June was born in May 1980', 'MMMM YYYY')
<Arrow [1980-05-01T00:00:00+00:00]>

Some ISO 8601 compliant strings are recognized and parsed without a format string:

>>> arrow.get('2013-09-30T15:34:00.000-07:00')
<Arrow [2013-09-30T15:34:00-07:00]>

Arrow objects can be instantiated directly too, with the same arguments as a datetime:

>>> arrow.get(2013, 5, 5)
<Arrow [2013-05-05T00:00:00+00:00]>

>>> arrow.Arrow(2013, 5, 5)
<Arrow [2013-05-05T00:00:00+00:00]>

Properties¶

Get a datetime or timestamp representation:

>>> a = arrow.utcnow()
>>> a.datetime
datetime.datetime(2013, 5, 7, 4, 38, 15, 447644, tzinfo=tzutc())

Get a naive datetime, and tzinfo:

>>> a.naive
datetime.datetime(2013, 5, 7, 4, 38, 15, 447644)

>>> a.tzinfo
tzutc()

Get any datetime value:

>>> a.year
2013

Call datetime functions that return properties:

>>> a.date()
datetime.date(2013, 5, 7)

>>> a.time()
datetime.time(4, 38, 15, 447644)

Replace & Shift¶

Get a new Arrow object, with altered attributes, just as you would with a datetime:

>>> arw = arrow.utcnow()
>>> arw
<Arrow [2013-05-12T03:29:35.334214+00:00]>

>>> arw.replace(hour=4, minute=40)
<Arrow [2013-05-12T04:40:35.334214+00:00]>

Or, get one with attributes shifted forward or backward:

>>> arw.shift(weeks=+3)
<Arrow [2013-06-02T03:29:35.334214+00:00]>

Even replace the timezone without altering other attributes:

>>> arw.replace(tzinfo='US/Pacific')
<Arrow [2013-05-12T03:29:35.334214-07:00]>

Move between the earlier and later moments of an ambiguous time:

>>> paris_transition = arrow.Arrow(2019, 10, 27, 2, tzinfo="Europe/Paris", fold=0)
>>> paris_transition
<Arrow [2019-10-27T02:00:00+02:00]>
>>> paris_transition.ambiguous
True
>>> paris_transition.replace(fold=1)
<Arrow [2019-10-27T02:00:00+01:00]>

Format¶

>>> arrow.utcnow().format('YYYY-MM-DD HH:mm:ss ZZ')
'2013-05-07 05:23:16 -00:00'

Convert¶

Convert from UTC to other timezones by name or tzinfo:

>>> utc = arrow.utcnow()
>>> utc
<Arrow [2013-05-07T05:24:11.823627+00:00]>

>>> utc.to('US/Pacific')
<Arrow [2013-05-06T22:24:11.823627-07:00]>

>>> utc.to(tz.gettz('US/Pacific'))
<Arrow [2013-05-06T22:24:11.823627-07:00]>

Or using shorthand:

>>> utc.to('local')
<Arrow [2013-05-06T22:24:11.823627-07:00]>

>>> utc.to('local').to('utc')
<Arrow [2013-05-07T05:24:11.823627+00:00]>

Humanize¶

Humanize relative to now:

>>> past = arrow.utcnow().shift(hours=-1)
>>> past.humanize()
'an hour ago'

Or another Arrow, or datetime:

>>> present = arrow.utcnow()
>>> future = present.shift(hours=2)
>>> future.humanize(present)
'in 2 hours'

Indicate time as relative or include only the distance

>>> present = arrow.utcnow()
>>> future = present.shift(hours=2)
>>> future.humanize(present)
'in 2 hours'
>>> future.humanize(present, only_distance=True)
'2 hours'

Indicate a specific time granularity (or multiple):

>>> present = arrow.utcnow()
>>> future = present.shift(minutes=66)
>>> future.humanize(present, granularity="minute")
'in 66 minutes'
>>> future.humanize(present, granularity=["hour", "minute"])
'in an hour and 6 minutes'
>>> present.humanize(future, granularity=["hour", "minute"])
'an hour and 6 minutes ago'
>>> future.humanize(present, only_distance=True, granularity=["hour", "minute"])
'an hour and 6 minutes'

Support for a growing number of locales (see locales.py for supported languages):

>>> future = arrow.utcnow().shift(hours=1)
>>> future.humanize(a, locale='ru')
'через 2 час(а,ов)'

Dehumanize¶

Take a human readable string and use it to shift into a past time:

>>> arw = arrow.utcnow()
>>> arw
<Arrow [2021-04-20T22:27:34.787885+00:00]>
>>> earlier = arw.dehumanize("2 days ago")
>>> earlier
<Arrow [2021-04-18T22:27:34.787885+00:00]>

Or use it to shift into a future time:

>>> arw = arrow.utcnow()
>>> arw
<Arrow [2021-04-20T22:27:34.787885+00:00]>
>>> later = arw.dehumanize("in a month")
>>> later
<Arrow [2021-05-18T22:27:34.787885+00:00]>

Support for a growing number of locales (see constants.py for supported languages):

>>> arw = arrow.utcnow()
>>> arw
<Arrow [2021-04-20T22:27:34.787885+00:00]>
>>> later = arw.dehumanize("एक माह बाद", locale="hi")
>>> later
<Arrow [2021-05-18T22:27:34.787885+00:00]>

Ranges & Spans¶

Get the time span of any unit:

>>> arrow.utcnow().span('hour')
(<Arrow [2013-05-07T05:00:00+00:00]>, <Arrow [2013-05-07T05:59:59.999999+00:00]>)

Or just get the floor and ceiling:

>>> arrow.utcnow().floor('hour')
<Arrow [2013-05-07T05:00:00+00:00]>

>>> arrow.utcnow().ceil('hour')
<Arrow [2013-05-07T05:59:59.999999+00:00]>

You can also get a range of time spans:

>>> start = datetime(2013, 5, 5, 12, 30)
>>> end = datetime(2013, 5, 5, 17, 15)
>>> for r in arrow.Arrow.span_range('hour', start, end):
...     print(r)
...
(<Arrow [2013-05-05T12:00:00+00:00]>, <Arrow [2013-05-05T12:59:59.999999+00:00]>)
(<Arrow [2013-05-05T13:00:00+00:00]>, <Arrow [2013-05-05T13:59:59.999999+00:00]>)
(<Arrow [2013-05-05T14:00:00+00:00]>, <Arrow [2013-05-05T14:59:59.999999+00:00]>)
(<Arrow [2013-05-05T15:00:00+00:00]>, <Arrow [2013-05-05T15:59:59.999999+00:00]>)
(<Arrow [2013-05-05T16:00:00+00:00]>, <Arrow [2013-05-05T16:59:59.999999+00:00]>)

Or just iterate over a range of time:

>>> start = datetime(2013, 5, 5, 12, 30)
>>> end = datetime(2013, 5, 5, 17, 15)
>>> for r in arrow.Arrow.range('hour', start, end):
...     print(repr(r))
...
<Arrow [2013-05-05T12:30:00+00:00]>
<Arrow [2013-05-05T13:30:00+00:00]>
<Arrow [2013-05-05T14:30:00+00:00]>
<Arrow [2013-05-05T15:30:00+00:00]>
<Arrow [2013-05-05T16:30:00+00:00]>

Factories¶

Use factories to harness Arrow’s module API for a custom Arrow-derived type. First, derive your type:

>>> class CustomArrow(arrow.Arrow):
...
...     def days_till_xmas(self):
...
...         xmas = arrow.Arrow(self.year, 12, 25)
...
...         if self > xmas:
...             xmas = xmas.shift(years=1)
...
...         return (xmas - self).days

Then get and use a factory for it:

>>> factory = arrow.ArrowFactory(CustomArrow)
>>> custom = factory.utcnow()
>>> custom
>>> <CustomArrow [2013-05-27T23:35:35.533160+00:00]>

>>> custom.days_till_xmas()
>>> 211

Supported Tokens¶

Use the following tokens for parsing and formatting. Note that they are not the same as the tokens for strptime:

	Token	Output
Year	YYYY	2000, 2001, 2002 … 2012, 2013
	YY	00, 01, 02 … 12, 13
Month	MMMM	January, February, March … 1
	MMM	Jan, Feb, Mar … 1
	MM	01, 02, 03 … 11, 12
	M	1, 2, 3 … 11, 12
Day of Year	DDDD	001, 002, 003 … 364, 365
	DDD	1, 2, 3 … 364, 365
Day of Month	DD	01, 02, 03 … 30, 31
	D	1, 2, 3 … 30, 31
	Do	1st, 2nd, 3rd … 30th, 31st
Day of Week	dddd	Monday, Tuesday, Wednesday … 2
	ddd	Mon, Tue, Wed … 2
	d	1, 2, 3 … 6, 7
ISO week date	W	2011-W05-4, 2019-W17
Hour	HH	00, 01, 02 … 23, 24
	H	0, 1, 2 … 23, 24
	hh	01, 02, 03 … 11, 12
	h	1, 2, 3 … 11, 12
AM / PM	A	AM, PM, am, pm 1
	a	am, pm 1
Minute	mm	00, 01, 02 … 58, 59
	m	0, 1, 2 … 58, 59
Second	ss	00, 01, 02 … 58, 59
	s	0, 1, 2 … 58, 59
Sub-second	S…	0, 02, 003, 000006, 123123123123… 3
Timezone	ZZZ	Asia/Baku, Europe/Warsaw, GMT … 4
	ZZ	-07:00, -06:00 … +06:00, +07:00, +08, Z
	Z	-0700, -0600 … +0600, +0700, +08, Z
Seconds Timestamp	X	1381685817, 1381685817.915482 … 5
ms or µs Timestamp	x	1569980330813, 1569980330813221

Footnotes

1(1,2,3,4): localization support for parsing and formatting
2(1,2): localization support only for formatting
3: the result is truncated to microseconds, with half-to-even rounding.
4: timezone names from tz database provided via dateutil package, note that abbreviations such as MST, PDT, BRST are unlikely to parse due to ambiguity. Use the full IANA zone name instead (Asia/Shanghai, Europe/London, America/Chicago etc).
5: this token cannot be used for parsing timestamps out of natural language strings due to compatibility reasons

Built-in Formats¶

There are several formatting standards that are provided as built-in tokens.

>>> arw = arrow.utcnow()
>>> arw.format(arrow.FORMAT_ATOM)
'2020-05-27 10:30:35+00:00'
>>> arw.format(arrow.FORMAT_COOKIE)
'Wednesday, 27-May-2020 10:30:35 UTC'
>>> arw.format(arrow.FORMAT_RSS)
'Wed, 27 May 2020 10:30:35 +0000'
>>> arw.format(arrow.FORMAT_RFC822)
'Wed, 27 May 20 10:30:35 +0000'
>>> arw.format(arrow.FORMAT_RFC850)
'Wednesday, 27-May-20 10:30:35 UTC'
>>> arw.format(arrow.FORMAT_RFC1036)
'Wed, 27 May 20 10:30:35 +0000'
>>> arw.format(arrow.FORMAT_RFC1123)
'Wed, 27 May 2020 10:30:35 +0000'
>>> arw.format(arrow.FORMAT_RFC2822)
'Wed, 27 May 2020 10:30:35 +0000'
 >>> arw.format(arrow.FORMAT_RFC3339)
'2020-05-27 10:30:35+00:00'
 >>> arw.format(arrow.FORMAT_W3C)
'2020-05-27 10:30:35+00:00'

Escaping Formats¶

Tokens, phrases, and regular expressions in a format string can be escaped when parsing and formatting by enclosing them within square brackets.

Tokens & Phrases¶

Any token or phrase can be escaped as follows:

>>> fmt = "YYYY-MM-DD h [h] m"
>>> arw = arrow.get("2018-03-09 8 h 40", fmt)
<Arrow [2018-03-09T08:40:00+00:00]>
>>> arw.format(fmt)
'2018-03-09 8 h 40'

>>> fmt = "YYYY-MM-DD h [hello] m"
>>> arw = arrow.get("2018-03-09 8 hello 40", fmt)
<Arrow [2018-03-09T08:40:00+00:00]>
>>> arw.format(fmt)
'2018-03-09 8 hello 40'

>>> fmt = "YYYY-MM-DD h [hello world] m"
>>> arw = arrow.get("2018-03-09 8 hello world 40", fmt)
<Arrow [2018-03-09T08:40:00+00:00]>
>>> arw.format(fmt)
'2018-03-09 8 hello world 40'

This can be useful for parsing dates in different locales such as French, in which it is common to format time strings as “8 h 40” rather than “8:40”.

Regular Expressions¶

You can also escape regular expressions by enclosing them within square brackets. In the following example, we are using the regular expression \s+ to match any number of whitespace characters that separate the tokens. This is useful if you do not know the number of spaces between tokens ahead of time (e.g. in log files).

>>> fmt = r"ddd[\s+]MMM[\s+]DD[\s+]HH:mm:ss[\s+]YYYY"
>>> arrow.get("Mon Sep 08 16:41:45 2014", fmt)
<Arrow [2014-09-08T16:41:45+00:00]>

>>> arrow.get("Mon \tSep 08   16:41:45     2014", fmt)
<Arrow [2014-09-08T16:41:45+00:00]>

>>> arrow.get("Mon Sep 08   16:41:45   2014", fmt)
<Arrow [2014-09-08T16:41:45+00:00]>

Punctuation¶

Date and time formats may be fenced on either side by one punctuation character from the following list: , . ; : ? ! " \` ' [ ] { } ( ) < >

>>> arrow.get("Cool date: 2019-10-31T09:12:45.123456+04:30.", "YYYY-MM-DDTHH:mm:ss.SZZ")
<Arrow [2019-10-31T09:12:45.123456+04:30]>

>>> arrow.get("Tomorrow (2019-10-31) is Halloween!", "YYYY-MM-DD")
<Arrow [2019-10-31T00:00:00+00:00]>

>>> arrow.get("Halloween is on 2019.10.31.", "YYYY.MM.DD")
<Arrow [2019-10-31T00:00:00+00:00]>

>>> arrow.get("It's Halloween tomorrow (2019-10-31)!", "YYYY-MM-DD")
# Raises exception because there are multiple punctuation marks following the date

Redundant Whitespace¶

Redundant whitespace characters (spaces, tabs, and newlines) can be normalized automatically by passing in the normalize_whitespace flag to arrow.get:

>>> arrow.get('\t \n  2013-05-05T12:30:45.123456 \t \n', normalize_whitespace=True)
<Arrow [2013-05-05T12:30:45.123456+00:00]>

>>> arrow.get('2013-05-05  T \n   12:30:45\t123456', 'YYYY-MM-DD T HH:mm:ss S', normalize_whitespace=True)
<Arrow [2013-05-05T12:30:45.123456+00:00]>