Arrow: Better dates & times for Python

Release v0.17.0 (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

  • Supports Python 2.7, 3.5, 3.6, 3.7, 3.8 and 3.9

  • Timezone-aware and UTC by default

  • Provides super-simple creation options for many common input scenarios

  • shift method with support for relative offsets, including weeks

  • Formats and parses strings automatically

  • Wide support for ISO 8601

  • Timezone conversion

  • Timestamp available as a property

  • Generates time spans, ranges, floors and ceilings for time frames ranging from microsecond to year

  • Humanizes and supports a growing list of contributed locales

  • Extensible for your own Arrow-derived types

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

>>> 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')
'1시간 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())

>>> a.timestamp
1367901495

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)'

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]>

API Guide

arrow.arrow

arrow.factory

arrow.api

arrow.locale