A minimal implementation of quarters so that we can use quarters in i…

…dtags.

tests/test_ttcal_quarter.py

@@ -0,0 +1,93 @@
+from datetime import date, datetime
+import ttcal
+import pytest
+
+
+@pytest.fixture
+def quarters():
+    return [
+        ttcal.Quarter(2005, 1),
+        ttcal.Quarter(),
+        ttcal.Quarter(2025, 4),
+    ]
+
+
+def test_stringification(quarters):
+    assert str(quarters[0]) == '1'
+
+
+def test_timetuple(quarters):
+    assert quarters[0].timetuple() == datetime(2005, 1, 1, 0, 0, 0)
+
+
+def test_range(quarters):
+    assert len(list(quarters[0].range())) == 90
+
+
+def test_between_tuple(quarters):
+    a, b = quarters[0].between_tuple()
+    assert a < b
+
+
+def test_middle(quarters):
+    assert quarters[0].middle == (ttcal.Day(2005, 2, 14))
+
+
+def test_unicode(quarters):
+    assert repr(quarters[0]) == 'Q(20051)'
+    assert str(quarters[0]) == '1'
+
+
+def test_month(quarters):
+    assert quarters[0].Month == ttcal.Month(2005, 1)
+
+
+def test_quarter(quarters):
+    assert int(quarters[0]) == int(quarters[0].Quarter)
+
+
+def test_hash(quarters):
+    assert hash(quarters[0]) == hash(ttcal.Quarter(2005, 1))
+
+
+def test_from_idtag(quarters):
+    """Test of the from_idtag method.
+    """
+    assert quarters[0].from_idtag('q20051') == quarters[0]
+
+
+def test_idtag(quarters):
+    """Test of the idtag method.
+    """
+    assert quarters[2].idtag() == 'q20254'
+
+
+def test_add(quarters):
+    """Test of the __add__ method.
+    """
+    assert quarters[0] + 2 == ttcal.Quarter(2005, 3)
+    assert 2 + quarters[0] == ttcal.Quarter(2005, 3)
+
+
+def test_sub(quarters):
+    """Test of the __sub__ method.
+    """
+    assert quarters[2] - 3 == ttcal.Quarter(2025, 1)
+
+
+def test_prev(quarters):
+    """Test of the prev method.
+    """
+    assert quarters[2].prev() == ttcal.Quarter(2025, 3)
+
+
+def test_next(quarters):
+    """Test of the next method.
+    """
+    assert quarters[0].next() == ttcal.Quarter(2005, 2)
+
+
+def test_format(quarters):
+    assert quarters[0].format('q') == '1'
+    assert quarters[0].format('Q') == '2005Q1'
+    assert quarters[0].format() == '2005Q1'

ttcal/__init__.py

@@ -8,17 +8,19 @@
 from .month import Month
 from .week import Week
 from .year import Year
+from .quarter import Quarter
 
 
 def from_idtag(idtag):
     """Return a class from idtag.
     """
     assert len(idtag) > 1
-    assert idtag[0] in 'wdmy'
+    assert idtag[0] in 'wdmqy'
 
     return {
         'w': Week,
         'd': Day,
         'm': Month,
+        'q': Quarter,
         'y': Year,
     }[idtag[0]].from_idtag(idtag)

ttcal/quarter.py

@@ -0,0 +1,210 @@
+"""
+quarter class.
+"""
+import datetime
+
+from . import Month
+from .calfns import chop, rangecmp, rangetuple
+from .day import Day
+from .year import Year
+
+
+class Quarter:  # pylint:disable=too-many-public-methods
+    """A single quarter.
+    """
+    def __init__(self, year=None, quarter=None):
+        super().__init__()
+        # if quarter is None:
+        if year is None:
+            year = datetime.date.today().year
+        if quarter is None:
+            quarter = 1
+        self.year = year
+        self.quarter = quarter
+        self.months = Year(year).quarters()[self.quarter-1]
+
+    def __int__(self):
+        return self.quarter
+
+    def range(self):
+        """Return an iterator for the range of `self`.
+        """
+        return self.dayiter()
+
+    def rangetuple(self):
+        """Return a pair of datetime objects containing quarter
+           (in a half-open interval).
+        """
+        return self.first.datetime(), (self + 1).first.datetime()
+
+    # def __lt__(self, other):
+    #     if isinstance(other, int):
+    #         return self.quarter < other
+    #     othr = rangetuple(other)
+    #     if othr is other:
+    #         return False
+    #     return rangecmp(self.rangetuple(), othr) < 0
+    #
+    # def __le__(self, other):
+    #     if isinstance(other, int):
+    #         return self.quarter <= other
+    #     othr = rangetuple(other)
+    #     if othr is other:
+    #         return False
+    #     return rangecmp(self.rangetuple(), othr) <= 0
+
+    def __eq__(self, other):
+        if isinstance(other, int):
+            return self.quarter == other
+        othr = rangetuple(other)
+        if othr is other:
+            return False
+        return rangecmp(self.rangetuple(), othr) == 0
+
+    def __ne__(self, other):
+        return not self == other
+
+    # def __gt__(self, other):
+    #     if isinstance(other, int):
+    #         return self.quarter > other
+    #     othr = rangetuple(other)
+    #     if othr is other:
+    #         return False
+    #     return rangecmp(self.rangetuple(), othr) > 0
+    #
+    # def __ge__(self, other):
+    #     if isinstance(other, int):
+    #         return self.quarter >= other
+    #     othr = rangetuple(other)
+    #     if othr is other:
+    #         return False
+    #     return rangecmp(self.rangetuple(), othr) >= 0
+
+    def timetuple(self):
+        """Returns a datetime at 00:00:00 on January 1st.
+        """
+        d = datetime.date(*self.first.datetuple())
+        t = datetime.time()
+        return datetime.datetime.combine(d, t)
+
+    @property
+    def first(self):
+        # The negative indexing here is due to the fact that the
+        # first quarter is list element 0 and so on.
+        return self.Year.quarters()[self.quarter-1][0].first
+
+    @property
+    def last(self):
+        return self.Year.quarters()[self.quarter-1][2].last
+
+    def between_tuple(self):  # pylint:disable=E0213
+        """Return a tuple of datetimes that is convenient for sql
+           `between` queries.
+        """
+        return (self.first.datetime(),
+                (self.last + 1).datetime() - datetime.timedelta(seconds=1))
+
+    @property
+    def Year(self):
+        """Return the year (for api completeness).
+        """
+        return Year(self.year)
+
+    @property
+    def Month(self):
+        """For orthogonality in the api.
+        """
+        return self.months[0]
+
+    @property
+    def middle(self):
+        """Return the day that splits the date range in half.
+        """
+        middle = (self.first.toordinal() + self.last.toordinal()) // 2
+        return Day.fromordinal(middle)
+
+    # def timetuple(self):
+    #     """Create timetuple from datetuple.
+    #        (to interact with datetime objects).
+    #     """
+    #     d = datetime.date(*self.datetuple())
+    #     t = datetime.time()
+    #     return datetime.datetime.combine(d, t)
+
+    def __repr__(self):
+        return f'Q({self.year}{self.quarter})'
+
+    def __str__(self):  # pragma: nocover
+        return str(self.quarter)
+
+    @property
+    def Quarter(self):
+        """Return the quarter (for api completeness).
+        """
+        return self
+
+    @classmethod
+    def from_idtag(cls, tag):
+        """quarter tags have the lower-case letter y + the four digit quarter,
+           eg. q20081.
+        """
+        y = int(tag[1:5])
+        q = int(tag[5])
+        return cls(year=y, quarter=q)
+
+    def idtag(self):
+        """quarter tags have the lower-case letter y + the four digit quarter,
+           eg. y2008.
+        """
+        return f'q{self.year}{self.quarter}'
+
+    def __add__(self, n):
+        """Add n quarters to self.
+        """
+        return Quarter(self.year, self.quarter + n)
+
+    def __radd__(self, n):
+        return self + n
+
+    def __sub__(self, n):
+        return self + (-n)
+
+    # rsub doesn't make sense
+
+    def prev(self):
+        """Previous quarter.
+        """
+        return self - 1
+
+    def next(self):
+        """Next quarter.
+        """
+        return self + 1
+
+    def __hash__(self):
+        return self.quarter
+
+    def dayiter(self):
+        """Yield all days in all months in quarter.
+        """
+        for m in self.months:
+            yield from m.days()
+
+    def _format(self, fmtchars):
+        # http://blog.tkbe.org/archive/date-filter-cheat-sheet/
+        for ch in fmtchars:
+            if ch == 'q':
+                yield str(self.quarter)
+            elif ch == 'Q':
+                yield f'{str(self.year)}Q{self.quarter}'
+            else:
+                yield ch
+
+    def format(self, fmt=None):
+        """Format according to format string. Default format is
+           four-digit-year and quearter-number.
+        """
+        if fmt is None:
+            fmt = "Q"
+        tmp = list(self._format(list(fmt)))
+        return ''.join(tmp)