gh-103072: Add a timestamp() method to datetime.date

Doc/library/datetime.rst

@@ -734,6 +734,15 @@ Instance methods:
    ``date.fromordinal(d.toordinal()) == d``.
 
 
+.. method:: date.timestamp()
+
+   Return POSIX timestamp corresponding to the :class:`.date`
+   instance. The return value is a :class:`float` similar to that
+   returned by :func:`time.time`.
+
+   .. versionadded:: next
+
+
 .. method:: date.weekday()
 
    Return the day of the week as an integer, where Monday is 0 and Sunday is 6.

Lib/_pydatetime.py

@@ -1241,6 +1241,11 @@ def weekday(self):
         "Return day of the week, where Monday == 0 ... Sunday == 6."
         return (self.toordinal() + 6) % 7
 
+    def timestamp(self):
+        """Return POSIX timestamp as float (midnight UTC)."""
+        epoch = date(1970, 1, 1)
+        return float((self.toordinal() - epoch.toordinal()) * 86400)
+
     # Day-of-the-week and week-of-the-year, according to ISO
 
     def isoweekday(self):

Lib/test/datetimetester.py

@@ -1207,6 +1207,26 @@ def test_strptime_leap_year(self):
             date.strptime('20-03-14', '%y-%m-%d')
             date.strptime('02-29,2024', '%m-%d,%Y')
 
+    @support.run_with_tz('UTC+0')
+    def test_timestamp(self):
+        t = date(1970, 1, 1)
+        self.assertEqual(t.timestamp(), 0.0)
+
+        t = date(2000, 1, 1)
+        self.assertEqual(t.timestamp(),946684800.0)
+
+        t = date(2025, 3, 14)
+        self.assertEqual(t, date.fromtimestamp(t.timestamp()))
+
+        for t in [date(2, 1, 1), date(9998, 12, 12)]:
+            try:
+                s = t.timestamp()
+            except OverflowError:
+                pass
+            else:
+                self.assertEqual(date.fromtimestamp(s), t)
+
+
 class SubclassDate(date):
     sub_var = 1
 

Misc/NEWS.d/next/Library/2025-03-14-09-44-00.gh-issue-103072.123yhr1.rst

@@ -0,0 +1 @@
+Added :func:`datetime.date.timestamp` to :class:`datetime.date`.

Modules/_datetimemodule.c

@@ -3868,6 +3868,20 @@ date_weekday(PyObject *self, PyObject *Py_UNUSED(dummy))
     return PyLong_FromLong(dow);
 }
 
+static PyObject *
+date_timestamp(PyObject *self, PyObject *Py_UNUSED(ignored))
+{
+    PyObject *ordinal_obj = date_toordinal(self, NULL);
+    if (!ordinal_obj) {
+        return NULL;
+    }
+    int days_since_epoch = PyLong_AsLong(ordinal_obj) - 719163;
+    Py_DECREF(ordinal_obj);
+    double timestamp = days_since_epoch * 86400.0;
+
+    return PyFloat_FromDouble(timestamp);
+}
+
 /* Pickle support, a simple use of __reduce__. */
 
 /* __getstate__ isn't exposed */
@@ -3946,6 +3960,9 @@ static PyMethodDef date_methods[] = {
      PyDoc_STR("Return the day of the week represented by the date.\n"
                "Monday == 0 ... Sunday == 6")},
 
+     {"timestamp", (PyCFunction)date_timestamp, METH_NOARGS,
+     PyDoc_STR("Return POSIX timestamp as float (midnight UTC).")},
+
     DATETIME_DATE_REPLACE_METHODDEF
 
     {"__replace__", _PyCFunction_CAST(datetime_date_replace), METH_FASTCALL | METH_KEYWORDS,