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diff --git a/docs/exercises/index.rst b/docs/exercises/index.rst new file mode 100644 index 0000000..e5e5783 --- /dev/null +++ b/docs/exercises/index.rst @@ -0,0 +1,242 @@ +Exercises +========= + +It is often useful to work through some examples in order to understand how a module works; on this page, there are several exercises of varying difficulty that you can use to learn how to use ``dateutil``. + +If you are interested in helping improve the documentation of ``dateutil``, it is recommended that you attempt to complete these exercises with no resources *other than dateutil's documentation*. If you find that the documentation is not clear enough to allow you to complete these exercises, open an issue on the `dateutil issue tracker <https://github.com/dateutil/dateutil/issues>`_ to let the developers know what part of the documentation needs improvement. + + +.. contents:: Table of Contents + :backlinks: top + :local: + + +.. _mlk-day-exercise: + +Martin Luther King Day +-------------------------------- + + + `Martin Luther King, Jr Day <https://en.wikipedia.org/wiki/Martin_Luther_King_Jr._Day>`_ is a US holiday that occurs every year on the third Monday in January? + + How would you generate a `recurrence rule <../rrule.html>`_ that generates Martin Luther King Day, starting from its first observance in 1986? + + +**Test Script** + +To solve this exercise, copy-paste this script into a document, change anything between the ``--- YOUR CODE ---`` comment blocks. + +.. raw:: html + + <details> + +.. code-block:: python3 + + # ------- YOUR CODE -------------# + from dateutil import rrule + + MLK_DAY = <<YOUR CODE HERE>> + + # -------------------------------# + + from datetime import datetime + MLK_TEST_CASES = [ + ((datetime(1970, 1, 1), datetime(1980, 1, 1)), + []), + ((datetime(1980, 1, 1), datetime(1989, 1, 1)), + [datetime(1986, 1, 20), + datetime(1987, 1, 19), + datetime(1988, 1, 18)]), + ((datetime(2017, 2, 1), datetime(2022, 2, 1)), + [datetime(2018, 1, 15, 0, 0), + datetime(2019, 1, 21, 0, 0), + datetime(2020, 1, 20, 0, 0), + datetime(2021, 1, 18, 0, 0), + datetime(2022, 1, 17, 0, 0)] + ), + ] + + def test_mlk_day(): + for (between_args, expected) in MLK_TEST_CASES: + assert MLK_DAY.between(*between_args) == expected + + if __name__ == "__main__": + test_mlk_day() + print('Success!') + +.. raw:: html + + </details> + +A solution to this problem is provided :doc:`here <solutions/mlk-day-rrule>`. + + +Next Monday meeting +------------------- + + A team has a meeting at 10 AM every Monday and wants a function that tells them, given a ``datetime.datetime`` object, what is the date and time of the *next* Monday meeting? This is probably best accomplished using a `relativedelta <../relativedelta.html>`_. + +**Test Script** + +To solve this exercise, copy-paste this script into a document, change anything between the ``--- YOUR CODE ---`` comment blocks. + +.. raw:: html + + <details> + + +.. code-block:: python3 + + # --------- YOUR CODE -------------- # + from dateutil import relativedelta + + def next_monday(dt): + <<YOUR CODE HERE>> + + # ---------------------------------- # + + from datetime import datetime + from dateutil import tz + + NEXT_MONDAY_CASES = [ + (datetime(2018, 4, 11, 14, 30, 15, 123456), + datetime(2018, 4, 16, 10, 0)), + (datetime(2018, 4, 16, 10, 0), + datetime(2018, 4, 16, 10, 0)), + (datetime(2018, 4, 16, 10, 30), + datetime(2018, 4, 23, 10, 0)), + (datetime(2018, 4, 14, 9, 30, tzinfo=tz.gettz('America/New_York')), + datetime(2018, 4, 16, 10, 0, tzinfo=tz.gettz('America/New_York'))), + ] + + def test_next_monday_1(): + for dt_in, dt_out in NEXT_MONDAY_CASES: + assert next_monday(dt_in) == dt_out + + if __name__ == "__main__": + test_next_monday_1() + print('Success!') + +.. raw:: html + + </details> + + +Parsing a local tzname +---------------------- + + Three-character time zone abbreviations are *not* unique in that they do not explicitly map to a time zone. A list of time zone abbreviations in use can be found `here <https://www.timeanddate.com/time/zones/>`_. This means that parsing a datetime string such as ``'2018-01-01 12:30:30 CST'`` is ambiguous without context. Using `dateutil.parser <../parser.html>`_ and `dateutil.tz <../tz.html>`_, it is possible to provide a context such that these local names are converted to proper time zones. + +Problem 1 +********* + Given the context that you will only be parsing dates coming from the continental United States, India and Japan, write a function that parses a datetime string and returns a timezone-aware ``datetime`` with an IANA-style timezone attached. + + Note: For the purposes of the experiment, you may ignore the portions of the United States like Arizona and parts of Indiana that do not observe daylight saving time. + +**Test Script** + +To solve this exercise, copy-paste this script into a document, change anything between the ``--- YOUR CODE ---`` comment blocks. + +.. raw:: html + + <details> + + +.. code-block:: python3 + + # --------- YOUR CODE -------------- # + from dateutil.parser import parse + from dateutil import tz + + def parse_func_us_jp_ind(): + <<YOUR CODE HERE>> + + # ---------------------------------- # + + from dateutil import tz + from datetime import datetime + + + PARSE_TZ_TEST_DATETIMES = [ + datetime(2018, 1, 1, 12, 0), + datetime(2018, 3, 20, 2, 0), + datetime(2018, 5, 12, 3, 30), + datetime(2014, 9, 1, 23) + ] + + PARSE_TZ_TEST_ZONES = [ + tz.gettz('America/New_York'), + tz.gettz('America/Chicago'), + tz.gettz('America/Denver'), + tz.gettz('America/Los_Angeles'), + tz.gettz('Asia/Kolkata'), + tz.gettz('Asia/Tokyo'), + ] + + def test_parse(): + for tzi in PARSE_TZ_TEST_ZONES: + for dt in PARSE_TZ_TEST_DATETIMES: + dt_exp = dt.replace(tzinfo=tzi) + dtstr = dt_exp.strftime('%Y-%m-%d %H:%M:%S %Z') + + dt_act = parse_func_us_jp_ind(dtstr) + assert dt_act == dt_exp + assert dt_act.tzinfo is dt_exp.tzinfo + + if __name__ == "__main__": + test_parse() + print('Success!') + +.. raw:: html + + </details> + + +Problem 2 +********* + Given the context that you will *only* be passed dates from India or Ireland, write a function that correctly parses all *unambiguous* time zone strings to aware datetimes localized to the correct IANA zone, and for *ambiguous* time zone strings default to India. + +**Test Script** + +To solve this exercise, copy-paste this script into a document, change anything between the ``--- YOUR CODE ---`` comment blocks. + + +.. raw:: html + + <details> + +.. code-block:: python3 + + # --------- YOUR CODE -------------- # + from dateutil.parser import parse + from dateutil import tz + + def parse_func_ind_ire(): + <<YOUR CODE HERE>> + + # ---------------------------------- # + ISRAEL = tz.gettz('Asia/Jerusalem') + INDIA = tz.gettz('Asia/Kolkata') + PARSE_IXT_TEST_CASE = [ + ('2018-02-03 12:00 IST+02:00', datetime(2018, 2, 3, 12, tzinfo=ISRAEL)), + ('2018-06-14 12:00 IDT+03:00', datetime(2018, 6, 14, 12, tzinfo=ISRAEL)), + ('2018-06-14 12:00 IST', datetime(2018, 6, 14, 12, tzinfo=INDIA)), + ('2018-06-14 12:00 IST+05:30', datetime(2018, 6, 14, 12, tzinfo=INDIA)), + ('2018-02-03 12:00 IST', datetime(2018, 2, 3, 12, tzinfo=INDIA)), + ] + + + def test_parse_ixt(): + for dtstr, dt_exp in PARSE_IXT_TEST_CASE: + dt_act = parse_func_ind_ire(dtstr) + assert dt_act == dt_exp, (dt_act, dt_exp) + assert dt_act.tzinfo is dt_exp.tzinfo, (dt_act, dt_exp) + + if __name__ == "__main__": + test_parse_ixt() + print('Success!') + +.. raw:: html + + </details> + |