To help you get started, we've collected the most common ways that croniter is being used within popular public projects.

Introduction

DISCLAIMER

UNMAINTAINED/ABANDONED CODE / DO NOT USE

Due to the new EU Cyber Resilience Act (as European Union), even if it was implied because there was no more activity, this repository is now explicitly declared unmaintained.

The content does not meet the new regulatory requirements and therefore cannot be deployed or distributed, especially in a European context.

This repository now remains online ONLY for public archiving, documentation and education purposes and we ask everyone to respect this.

As stated, the maintainers stopped development and therefore all support some time ago, and make this declaration on December 15, 2024.

We may also unpublish soon (as in the following monthes) any published ressources tied to this project (pypi, the repositories, ...). So, please don't rely on it after March 15, 2025 and adapt whatever project which used this code.

croniter provides iteration for the datetime object with a cron like format.

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/ __| '__/ _ \| '_ \| | __/ _ \ '__|
| (__| | | (_) | | | | | ||  __/ |
\___|_|  \___/|_| |_|_|\__\___|_|

Website:

Build Badge

Usage

A simple example:

>>> from croniter import croniter
>>> from datetime import datetime
>>> base = datetime(2010, 1, 25, 4, 46)
>>> iter = croniter('*/5 * * * *', base)  # every 5 minutes
>>> print(iter.get_next(datetime))   # 2010-01-25 04:50:00
>>> print(iter.get_next(datetime))   # 2010-01-25 04:55:00
>>> print(iter.get_next(datetime))   # 2010-01-25 05:00:00
>>>
>>> iter = croniter('2 4 * * mon,fri', base)  # 04:02 on every Monday and Friday
>>> print(iter.get_next(datetime))   # 2010-01-26 04:02:00
>>> print(iter.get_next(datetime))   # 2010-01-30 04:02:00
>>> print(iter.get_next(datetime))   # 2010-02-02 04:02:00
>>>
>>> iter = croniter('2 4 1 * wed', base)  # 04:02 on every Wednesday OR on 1st day of month
>>> print(iter.get_next(datetime))   # 2010-01-27 04:02:00
>>> print(iter.get_next(datetime))   # 2010-02-01 04:02:00
>>> print(iter.get_next(datetime))   # 2010-02-03 04:02:00
>>>
>>> iter = croniter('2 4 1 * wed', base, day_or=False)  # 04:02 on every 1st day of the month if it is a Wednesday
>>> print(iter.get_next(datetime))   # 2010-09-01 04:02:00
>>> print(iter.get_next(datetime))   # 2010-12-01 04:02:00
>>> print(iter.get_next(datetime))   # 2011-06-01 04:02:00
>>>
>>> iter = croniter('0 0 * * sat#1,sun#2', base)  # 1st Saturday, and 2nd Sunday of the month
>>> print(iter.get_next(datetime))   # 2010-02-06 00:00:00
>>>
>>> iter = croniter('0 0 * * 5#3,L5', base)  # 3rd and last Friday of the month
>>> print(iter.get_next(datetime))   # 2010-01-29 00:00:00
>>> print(iter.get_next(datetime))   # 2010-02-19 00:00:00

All you need to know is how to use the constructor and the get_next method, the signature of these methods are listed below:

>>> def __init__(self, cron_format, start_time=time.time(), day_or=True)

croniter iterates along with cron_format from start_time. cron_format is min hour day month day_of_week, you can refer to for more details. The day_or switch is used to control how croniter handles day and day_of_week entries. Default option is the cron behaviour, which connects those values using OR. If the switch is set to False, the values are connected using AND. This behaves like fcron and enables you to e.g. define a job that executes each 2nd Friday of a month by setting the days of month and the weekday. :

>>> def get_next(self, ret_type=float)

get_next calculates the next value according to the cron expression and returns an object of type ret_type. ret_type should be a float or a datetime object.

Supported added for get_prev method. (>= 0.2.0):

>>> base = datetime(2010, 8, 25)
>>> itr = croniter('0 0 1 * *', base)
>>> print(itr.get_prev(datetime))  # 2010-08-01 00:00:00
>>> print(itr.get_prev(datetime))  # 2010-07-01 00:00:00
>>> print(itr.get_prev(datetime))  # 2010-06-01 00:00:00

You can validate your crons using is_valid class method. (>= 0.3.18):

>>> croniter.is_valid('0 0 1 * *')  # True
>>> croniter.is_valid('0 wrong_value 1 * *')  # False

About DST

Be sure to init your croniter instance with a TZ aware datetime for this to work!

Example using pytz:

>>> import pytz
>>> tz = pytz.timezone("Europe/Paris")
>>> local_date = tz.localize(datetime(2017, 3, 26))
>>> val = croniter('0 0 * * *', local_date).get_next(datetime)

Example using python_dateutil:

>>> import dateutil.tz
>>> tz = dateutil.tz.gettz('Asia/Tokyo')
>>> local_date = datetime(2017, 3, 26, tzinfo=tz)
>>> val = croniter('0 0 * * *', local_date).get_next(datetime)

Example using python built in module:

>>> from datetime import datetime, timezone
>>> local_date = datetime(2017, 3, 26, tzinfo=timezone.utc)
>>> val = croniter('0 0 * * *', local_date).get_next(datetime)

About second repeats

Croniter is able to do second repetition crontabs form and by default seconds are the 6th field:

>>> base = datetime(2012, 4, 6, 13, 26, 10)
>>> itr = croniter('* * * * * 15,25', base)
>>> itr.get_next(datetime) # 4/6 13:26:15
>>> itr.get_next(datetime) # 4/6 13:26:25
>>> itr.get_next(datetime) # 4/6 13:27:15

You can also note that this expression will repeat every second from the start datetime.:

>>> croniter('* * * * * *', local_date).get_next(datetime)

You can also use seconds as first field:

>>> itr = croniter('15,25 * * * * *', base, second_at_beginning=True)

About year

Croniter also support year field. Year presents at the seventh field, which is after second repetition. The range of year field is from 1970 to 2099. To ignore second repetition, simply set second to 0 or any other const:

>>> base = datetime(2012, 4, 6, 2, 6, 59)
>>> itr = croniter('0 0 1 1 * 0 2020/2', base)
>>> itr.get_next(datetime) # 2020 1/1 0:0:0
>>> itr.get_next(datetime) # 2022 1/1 0:0:0
>>> itr.get_next(datetime) # 2024 1/1 0:0:0

Support for start_time shifts

See , You can set start_time=, then expand_from_start_time=True for your generations to be computed from start_time instead of calendar days:

>>> from pprint import pprint
>>> iter = croniter('0 0 */7 * *', start_time=datetime(2024, 7, 11), expand_from_start_time=True);pprint([iter.get_next(datetime) for a in range(10)])
[datetime.datetime(2024, 7, 18, 0, 0),
 datetime.datetime(2024, 7, 25, 0, 0),
 datetime.datetime(2024, 8, 4, 0, 0),
 datetime.datetime(2024, 8, 11, 0, 0),
 datetime.datetime(2024, 8, 18, 0, 0),
 datetime.datetime(2024, 8, 25, 0, 0),
 datetime.datetime(2024, 9, 4, 0, 0),
 datetime.datetime(2024, 9, 11, 0, 0),
 datetime.datetime(2024, 9, 18, 0, 0),
 datetime.datetime(2024, 9, 25, 0, 0)]
>>> # INSTEAD OF THE DEFAULT BEHAVIOR:
>>> iter = croniter('0 0 */7 * *', start_time=datetime(2024, 7, 11), expand_from_start_time=False);pprint([iter.get_next(datetime) for a in range(10)])
[datetime.datetime(2024, 7, 15, 0, 0),
 datetime.datetime(2024, 7, 22, 0, 0),
 datetime.datetime(2024, 7, 29, 0, 0),
 datetime.datetime(2024, 8, 1, 0, 0),
 datetime.datetime(2024, 8, 8, 0, 0),
 datetime.datetime(2024, 8, 15, 0, 0),
 datetime.datetime(2024, 8, 22, 0, 0),
 datetime.datetime(2024, 8, 29, 0, 0),
 datetime.datetime(2024, 9, 1, 0, 0),
 datetime.datetime(2024, 9, 8, 0, 0)]

Testing if a date matches a crontab

Test for a match with (>=0.3.32):

>>> croniter.match("0 0 * * *", datetime(2019, 1, 14, 0, 0, 0, 0))
True
>>> croniter.match("0 0 * * *", datetime(2019, 1, 14, 0, 2, 0, 0))
False
>>>
>>> croniter.match("2 4 1 * wed", datetime(2019, 1, 1, 4, 2, 0, 0)) # 04:02 on every Wednesday OR on 1st day of month
True
>>> croniter.match("2 4 1 * wed", datetime(2019, 1, 1, 4, 2, 0, 0), day_or=False) # 04:02 on every 1st day of the month if it is a Wednesday
False

Testing if a crontab matches in datetime range

Test for a match_range with (>=2.0.3):

>>> croniter.match_range("0 0 * * *", datetime(2019, 1, 13, 0, 59, 0, 0), datetime(2019, 1, 14, 0, 1, 0, 0))
True
>>> croniter.match_range("0 0 * * *", datetime(2019, 1, 13, 0, 1, 0, 0), datetime(2019, 1, 13, 0, 59, 0, 0))
False
>>> croniter.match_range("2 4 1 * wed", datetime(2019, 1, 1, 3, 2, 0, 0), datetime(2019, 1, 1, 5, 1, 0, 0))
# 04:02 on every Wednesday OR on 1st day of month
True
>>> croniter.match_range("2 4 1 * wed", datetime(2019, 1, 1, 3, 2, 0, 0), datetime(2019, 1, 1, 5, 2, 0, 0), day_or=False)
# 04:02 on every 1st day of the month if it is a Wednesday
False

Gaps between date matches

For performance reasons, croniter limits the amount of CPU cycles spent attempting to find the next match. Starting in v0.3.35, this behavior is configurable via the max_years_between_matches parameter, and the default window has been increased from 1 year to 50 years.

The defaults should be fine for many use cases. Applications that evaluate multiple cron expressions or handle cron expressions from untrusted sources or end-users should use this parameter. Iterating over sparse cron expressions can result in increased CPU consumption or a raised CroniterBadDateError exception which indicates that croniter has given up attempting to find the next (or previous) match. Explicitly specifying max_years_between_matches provides a way to limit CPU utilization and simplifies the iterable interface by eliminating the need for CroniterBadDateError. The difference in the iterable interface is based on the reasoning that whenever max_years_between_matches is explicitly agreed upon, there is no need for croniter to signal that it has given up; simply stopping the iteration is preferable.

This example matches 4 AM Friday, January 1st. Since January 1st isn't often a Friday, there may be a few years between each occurrence. Setting the limit to 15 years ensures all matches:

>>> it = croniter("0 4 1 1 fri", datetime(2000,1,1), day_or=False, max_years_between_matches=15).all_next(datetime)
>>> for i in range(5):
...     print(next(it))
...
2010-01-01 04:00:00
2016-01-01 04:00:00
2021-01-01 04:00:00
2027-01-01 04:00:00
2038-01-01 04:00:00

However, when only concerned with dates within the next 5 years, simply set max_years_between_matches=5 in the above example. This will result in no matches found, but no additional cycles will be wasted on unwanted matches far in the future.

Iterating over a range using cron

Find matches within a range using the croniter_range() function. This is much like the builtin range(start,stop,step) function, but for dates. The step argument is a cron expression. Added in (>=0.3.34)

List the first Saturday of every month in 2019:

>>> from croniter import croniter_range
>>> for dt in croniter_range(datetime(2019, 1, 1), datetime(2019, 12, 31), "0 0 * * sat#1"):
>>>     print(dt)

Hashed expressions

croniter supports Jenkins-style hashed expressions, using the "H" definition keyword and the required hash_id keyword argument. Hashed expressions remain consistent, given the same hash_id, but different hash_ids will evaluate completely different to each other. This allows, for example, for an even distribution of differently-named jobs without needing to manually spread them out.

> >>> itr = croniter("H H * * ", hash_id="hello") > >>> itr.get_next(datetime) datetime.datetime(2021, 4, 10, > 11, 10) >>> itr.get_next(datetime) datetime.datetime(2021, > 4, 11, 11, 10) >>> itr = croniter("H H * ", > hash_id="hello") >>> itr.get_next(datetime) > datetime.datetime(2021, 4, 10, 11, 10) >>> itr = croniter("H > H * *", hash_id="bonjour") >>> itr.get_next(datetime) > datetime.datetime(2021, 4, 10, 20, 52)

Random expressions

Random "R" definition keywords are supported, and remain consistent only within their croniter() instance.

> >>> itr = croniter("R R * * ") >>> > itr.get_next(datetime) datetime.datetime(2021, 4, 10, 22, 56) > >>> itr.get_next(datetime) datetime.datetime(2021, 4, 11, > 22, 56) >>> itr = croniter("R R * *") >>> > itr.get_next(datetime) datetime.datetime(2021, 4, 11, 4, 19)

Note about Ranges

Note that as a deviation from cron standard, croniter is somehow laxist with ranges and will allow ranges of Jan-Dec, & Sun-Sat in reverse way and interpret them as following examples:

> - Apr-Jan: from April to january > - Sat-Sun: Saturday, Sunday > - Wed-Sun: Wednesday to Saturday, Sunday

Please note that if a /step is given, it will be respected.

Note about Sunday

Note that as a deviation from cron standard, croniter like numerous cron implementations supports SUNDAY to be expressed as DAY7, allowing such expressions:

> - 0 0 * * 7 > - 0 0 * * 6-7 > - 0 0 * * 6,7

Keyword expressions

Vixie cron-style "@" keyword expressions are supported. What they evaluate to depends on whether you supply hash_id: no hash_id corresponds to Vixie cron definitions (exact times, minute resolution), while with hash_id corresponds to Jenkins definitions (hashed within the period, second resolution).

> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >

Keyword	No hash_id	With hash_id
@midnight	0 0 * * *	H H(0-2) * * * H
@hourly	0 * * * *	H * * * * H
@daily	0 0 * * *	H H * * * H
@weekly	0 0 * * 0	H H * * H H
@monthly	0 0 1 * *	H H H * * H
@yearly	0 0 1 1 *	H H H H * H
@annually	0 0 1 1 *	H H H H * H

Upgrading

To 2.0.0

• Install or upgrade pytz by using version specified requirements/base.txt if you have it installed <=2021.1.

Develop this package

git clone https://github.com/kiorky/croniter.git
cd croniter
virtualenv --no-site-packages venv3
venv3/bin/pip install --upgrade -r requirements/test.txt -r requirements/lint.txt -r requirements/format.txt -r requirements/tox.txt
venv3/bin/black src/
venv3/bin/isort src/
venv3/bin/tox --current-env -e fmt,lint,test

Testing under py2

Install prerequisisites :

# install py 2 with eg: apt install python2.7
mkdir venv2 && curl -sSL "https://github.com/pypa/get-virtualenv/blob/20.27.0/public/2.7/virtualenv.pyz?raw=true" > venv2/venv && python2 venv2/venv venv2
venv2/bin/python2 -m pip install -r ./requirements/test.txt

Run tests:

./venv2/bin/pytest src

Make a new release

We use zest.fullreleaser, a great release infrastructure.

Do and follow these instructions :

venv3/bin/pip install --upgrade -r requirements/release.txt
./release.sh

Contributors

Thanks to all who have contributed to this project! If you have contributed and your name is not listed below please let us know.

> - Aarni Koskela (akx) > - chris-baynes > - djmitche > - evanpurkhiser > - GreatCombinator > - Hinnack > - ipartola > - jlsandell > - kiorky > - lowell80 (Kintyre) > - mag009 > - mrmachine > - Ryan Finnie (rfinnie) > - salitaba > - scop > - shazow > - yuzawa-san > - zed2015

Changelog

6.0.0 (2024-12-17)

• Announce for now that croniter dev is ended (CRA).

• Rework timestamp_to_datetime to use whatever timezone [kiorky]

• Make datetime_to_timestamp & timestamp_to_datetime public [kiorky]

• Fix EPOCH calculation in case of non UTC & 32 bits based systems [kiorky]

• Apply isort formatter [kiorky]

• Reintegrate test_speed [kiorky]

• Apply black formatter [evanpurkhiser, kiorky]

• Code quality changes [evanpurkhiser, kiorky]

  • Remove unused _get_caller_globals_and_locals [evanpurkhiser]
  • Remove single-use bad_length [evanpurkhiser]
  • Remove unused days in proc_month [evanpurkhiser]
  • Use field_index over i for readability [evanpurkhiser]
  • Always use """ for docstrings [evanpurkhiser]
  • Make helper instance methods that do not use self static [evanpurkhiser]
  • Remove unusd call to sys.exc_info [evanpurkhiser]
  • Remove unused ALPHAS [evanpurkhiser]
  • Improve croniter.expand documentation [evanpurkhiser]

5.0.1 (2024-10-29)

• Community wanted: Reintroduce 7 as DayOfWeek in deviation from standard cron (#90). [kiorky]

4.0.0 (2024-10-28)

• Remove DayOfWeek alias 7 to DayOfWeek 0 to stick to standard cron (#90). [kiorky]
• Fix DOW ranges calculations when lastday is a Sunday. [kiorky]

3.0.4 (2024-10-25)

• Fix overflow on 32bits systems (#87) [kiorky]
• Fix python2 testing (related to #93) [kiorky]
• Modernize packaging. Special thanks to Aarni Koskela (akx) for all the inputs. [kiorky, akx]

3.0.3 (2024-07-26)

• fix lint [kiorky]

3.0.2 (2024-07-26)

• Fix start_time not respected in get_next/get_prev/all_next/all_prev (#86) [hesstobi, kiorky]

3.0.1 (2024-07-25)

• Add an update_current argument to get_next/get_prev/all_next/all_prev to facilitate writing of some downstream code, see #83. [kiorky]

3.0.0 (2024-07-23)

• Support for year field [zhouyizhen, kiorky]
• Better support for 6 fields (second), and 7 fields crons [zhouyizhen, kiorky]
• Better fix hashed expressions omitting some entries (#82, #42, #30) fix is retained over #42 initial fix [zhouyizhen, kiorky]
• Ensure match return false when not time available (#81) [zhouyizhen, kiorky]

2.0.7 (2024-07-16)

• fix doc

2.0.6 (2024-07-16)

• Implement second_at_beginning [zhouyizhen, kiorky]
• Support question mark as wildcard [zhouyizhen, kiorky]
• Support to start a cron from a reference start time [mghextreme, kiorky]

2.0.5 (2024-04-20)

• No changes, fix lint [kiorky]

2.0.4 (2024-04-20)

• Support hashid strings in is_valid [george-kuanli-peng, kiorky]
• Avoid over-optimization in crontab expansions [Cherie0125, liqirui <>, kiorky]

2.0.3 (2024-03-19)

• Add match_range function [salitaba]

2.0.2 (2024-02-29)

• fix leap year (29 days in February) [zed2015]

2.0.1 (2023-10-11)

• Fix release issue [kiorky]

2.0.0 (2023-10-10)

• Add Python 3.12 support [rafsaf]
• Make major release instructions [kiorky]

1.4.1 (2023-06-15)

• Make a retrocompatible version of 1.4.0 change about supporting VIXIECRON bug. (fix #47) [kiorky]

1.4.0 (2023-06-15)

• Added "implement_cron_bug" flag to make the cron parser compatible with a bug in Vixie/ISC Cron [kiorky, David White <>] WARNING: EXPAND METHOD CHANGES RETURN VALUE

1.3.15 (2023-05-25)

• Fix hashed expressions omitting some entries [@waltervos/Walter Vos <>]
• Enhance .match() precision for 6 position expressions [@szpol/szymon <>]

1.3.14 (2023-04-12)

• Lint

1.3.13 (2023-04-12)

• Add check for range begin/end

1.3.12 (2023-04-12)

• restore py2 compat

1.3.11 (2023-04-12)

• Do not expose i into global namespace

1.3.10 (2023-04-07)

• Fix DOW hash parsing [kiorky]
• better error handling on py3 [kiorky]

1.3.8 (2022-11-22)

• Add Python 3.11 support and move docs files to main folder [rafsaf]

1.3.7 (2022-09-06)

• fix tests
• Fix croniter_range infinite loop [Shachar Snapiri <>]

1.3.5 (2022-05-14)

• Add Python 3.10 support [eelkevdbos]

1.3.4 (2022-02-18)

• Really fix compat for tests under py27 [kiorky]

1.3.3 (2022-02-18)

• Fix compat for tests under py27 [kiorky]

1.3.2 (2022-02-18)

• Fix #12: regressions with set_current [kiorky, agateblue]

1.3.1 (2022-02-15)

• Restore compat with python2 [kiorky]

1.3.0 (2022-02-15)

• Add a way to make next() easier to use. This fixes #11 [kiorky]

1.2.0 (2022-01-14)

• Enforce validation for day=1. Before this release we used to support day=0 and it was silently glided to day=1 to support having both day in day in 4th field when it came to have 6fields cron forms (second repeat). It will now raises a CroniterBadDateError. See [kiorky]

1.1.0 (2021-12-03)

• Enforce validation for month=1. Before this release we used to support month=0 and it was silently glided to month=1 to support having both day in month in 4th field when it came to have 6fields cron forms (second repeat). It will now raises a CroniterBadDateError. See [kiorky]

1.0.15 (2021-06-25)

• restore py2 [kiorky]

1.0.14 (2021-06-25)

• better type checks [kiorky]

1.0.13 (2021-05-06)

• Fix ZeroDivisionError with * * R/0 * * [cuu508]

1.0.12 (2021-04-13)

• Add support for hashed/random/keyword expressions Ryan Finnie (rfinnie)
• Review support support for hashed/random/keyword expression and add expanders reactor [ kiorky ]

1.0.11 (2021-04-07)

• fix bug: bad case:0 6 30 3 * [zed2015(zhangchi)]
• Add support for L in the day_of_week component. This enable expressions like * * * * L4, which means last Thursday of the month. This resolves #159. [Kintyre]
• Create CroniterUnsupportedSyntaxError exception for situations where CRON syntax may be valid but some combinations of features is not supported. Currently, this is used when the day_of_week component has a combination of literal values and nth/last syntax at the same time. For example, 0 0 * * 1,L6 or 0 0 * * 15,sat#1 will both raise this exception because of mixing literal days of the week with nth-weekday or last-weekday syntax. This may impact existing cron expressions in prior releases, because 0 0 * * 15,sat#1 was previously allowed but incorrectly handled. [Kintyre]
• Update croniter_range() to allow an alternate croniter class to be used. Helpful when using a custom class derived from croniter. [Kintyre]

1.0.10 (2021-03-25)

• Remove external library natsort. Sorting of cron expression components now handled with sorted() with a custom key function. [Kintyre]

1.0.9 (2021-03-23)

• Remove futures dependency [kiorky]

1.0.8 (2021-03-06)

• Update _expand to lowercase each component of the expression. This is in relation to #157. With this change, croniter accepts and correctly handles * * 10-L * *. [cuu508]

1.0.7 (2021-03-02)

• Fix _expand to reject int literals with underscores [cuu508]
• Remove a debug statement to make flake8 happy [cuu508]

1.0.6 (2021-02-01)

• Fix combination of star and invalid expression bugs [kiorky]

1.0.5 (2021-01-29)

• Security fix: fix overflow when using cron ranges [kiorky]

1.0.4 (2021-01-29)

• Spelling fix release

1.0.3 (2021-01-29)

• Fix #155: raise CroniterBadCronError when error syntax [kiorky]

1.0.2 (2021-01-19)

• Fix match when datetime has microseconds [kiorky]

1.0.1 (2021-01-06)

• no changes, just to make sense with new semver2 (making croniter on a stable state) [kiorky]

0.3.37 (2020-12-31)

• Added Python 3.8 and 3.9 support [eumiro]

0.3.36 (2020-11-02)

• Updated docs section regarding max_years_between_matches to be more shorter and hopefully more relevant. [Kintyre]
• Don't install tests [scop]

0.3.35 (2020-10-11)

• Handle L in ranges. This fixes #142. [kiorky]
• Add a new initialization parameter max_years_between_matches to support finding the next/previous date beyond the default 1 year window, if so desired. Updated README to include additional notes and example of this usage. Fixes #145. [Kintyre]
• The croniter_range() function was updated to automatically determines the appropriate max_years_between_matches value, this preventing handling of the CroniterBadDateError exception. [Kintyre]
• Updated exception handling classes: CroniterBadDateError now only applies during date finding operations (next/prev), and all parsing errors can now be caught using CroniterBadCronError. The CroniterNotAlphaError exception is now a subclass of CroniterBadCronError. A brief description of each exception class was added as an inline docstring. [Kintyre]
• Updated iterable interfaces to replace the CroniterBadDateError with StopIteration if (and only if) the max_years_between_matches argument is provided. The rationale here is that if the user has specified the max tolerance between matches, then there's no need to further inform them of no additional matches. Just stop the iteration. This also keeps backwards compatibility. [Kintyre]
• Minor docs update [Kintyre]

0.3.34 (2020-06-19)

• Feat croniter_range(start, stop, cron) [Kintyre]
• Optimization for poorly written cron expression [Kintyre]

0.3.33 (2020-06-15)

• Make dateutil tz support more official [Kintyre]
• Feat/support for day or [田口信元]

0.3.32 (2020-05-27)

• document seconds repeats, fixes #122 [kiorky]
• Implement match method, fixes #54 [kiorky]
• Adding tests for #127 (test more DSTs and croniter behavior around) [kiorky]
• Changed lag_hours comparison to absolute to manage dst boundary when getting previous [Sokkka]

0.3.31 (2020-01-02)

• Fix get_next() when start_time less then 1s before next instant [AlexHill]

0.3.30 (2019-04-20)

• credits

0.3.29 (2019-03-26)

• credits
• history stripping (security)
• Handle -Sun notation, This fixes #119. [kiorky]
• Handle invalid ranges correctly, This fixes #114. [kiorky]

0.3.25 (2018-08-07)

• Pypi hygiene [hugovk]

0.3.24 (2018-06-20)

• fix #107: microsecond threshold [kiorky]

0.3.23 (2018-05-23)

• fix get_next while preserving the fix of get_prev in 7661c2aaa [Avikam Agur <>]

0.3.22 (2018-05-16)

• Don't count previous minute if now is dynamic If the code is triggered from 5-asterisk based cron get_prev based on datetime.now() is expected to return current cron iteration and not previous execution. [Igor Khrol <>]

0.3.20 (2017-11-06)

• More DST fixes [Kevin Rose <>]

0.3.19 (2017-08-31)

• fix #87: backward dst changes [kiorky]

0.3.18 (2017-08-31)

• Add is valid method, refactor errors [otherpirate, Mauro Murari <>]

0.3.17 (2017-05-22)

• DOW occurrence sharp style support. [kiorky, Kengo Seki <>]

0.3.16 (2017-03-15)

• Better test suite []
• DST support [kiorky]

0.3.15 (2017-02-16)

• fix bug around multiple conditions and range_val in _get_prev_nearest_diff. []

0.3.14 (2017-01-25)

• issue #69: added day_or option to change behavior when day-of-month and day-of-week is given [Andreas Vogl <>]

0.3.13 (2016-11-01)

• Real fix for #34 []
• Modernize test infra []
• Release as a universal wheel []
• Raise ValueError on negative numbers []
• Compare types using "issubclass" instead of exact match []
• Implement step cron with a variable base []

0.3.12 (2016-03-10)

• support setting ret_type in __init__ [Brent Tubbs <>]

0.3.11 (2016-01-13)

• Bug fix: The get_prev API crashed when last day of month token was used. Some essential logic was missing. [Iddo Aviram <>]

0.3.10 (2015-11-29)

• The functionality of 'l' as day of month was broken, since the month variable was not properly updated [Iddo Aviram <>]

0.3.9 (2015-11-19)

• Don't use datetime functions python 2.6 doesn't support [petervtzand]

0.3.8 (2015-06-23)

• Truncate microseconds by setting to 0 [Corey Wright]

0.3.7 (2015-06-01)

• converting sun in range sun-thu transforms to int 0 which is recognized as empty string; the solution was to convert sun to string "0"

0.3.6 (2015-05-29)

• Fix default behavior when no start_time given Default value for start_time parameter is calculated at module init time rather than call time.
• Fix timezone support and stop depending on the system time zone

0.3.5 (2014-08-01)

• support for 'l' (last day of month)

0.3.4 (2014-01-30)

• Python 3 compat
• QA Release

0.3.3 (2012-09-29)

• proper packaging