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Issue #1289118: datetime.timedelta objects can now be multiplied by float

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and divided by float and int objects.
This commit is contained in:
Alexander Belopolsky 2010-05-31 17:33:47 +00:00
parent 9103597ee7
commit 1790bc43bf
4 changed files with 191 additions and 13 deletions
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14
Doc/library/datetime.rst
View file

@ -220,12 +220,20 @@ Supported operations:
| | In general, *t1* \* i == *t1* \* (i-1) + *t1* |
| | is true. (1) |
+--------------------------------+-----------------------------------------------+
| ``t1 = t2 * f or t1 = f * t2`` | Delta multiplied by a float. The result is |
| | rounded to the nearest multiple of |
| | timedelta.resolution using round-half-to-even.|
+--------------------------------+-----------------------------------------------+
| ``f = t2 / t3`` | Division (3) of *t2* by *t3*. Returns a |
| | :class:`float` object. |
+--------------------------------+-----------------------------------------------+
| ``t1 = t2 / f or t1 = t2 / i`` | Delta divided by a float or an int. The result|
| | is rounded to the nearest multiple of |
| | timedelta.resolution using round-half-to-even.|
+--------------------------------+-----------------------------------------------+
| ``t1 = t2 // i`` or | The floor is computed and the remainder (if |
| ``t1 = t2 // t3`` | any) is thrown away. In the second case, an |
| | integer is returned (3) |
| | integer is returned. (3) |
+--------------------------------+-----------------------------------------------+
| ``t1 = t2 % t3`` | The remainder is computed as a |
| | :class:`timedelta` object. (3) |
@ -267,7 +275,9 @@ objects (see below).
.. versionadded:: 3.2
Floor division and true division of a :class:`timedelta` object by
another :class:`timedelta` object are now supported, as are
remainder operations and the :func:`divmod` function.
remainder operations and the :func:`divmod` function. True
division and multiplication of a :class:`timedelta` object by
a :class:`float` object are now supported.
Comparisons of :class:`timedelta` objects are supported with the

72
Lib/test/test_datetime.py
View file

@ -25,6 +25,16 @@
OTHERSTUFF = (10, 34.5, "abc", {}, [], ())
# XXX Copied from test_float.
INF = float("inf")
NAN = float("nan")
# decorator for skipping tests on non-IEEE 754 platforms
requires_IEEE_754 = unittest.skipUnless(
float.__getformat__("double").startswith("IEEE"),
"test requires IEEE 754 doubles")
#############################################################################
# module tests
@ -225,6 +235,36 @@ def test_computations(self):
eq(c//1000, td(0, 0, 1))
eq(a//10, td(0, 7*24*360))
eq(a//3600000, td(0, 0, 7*24*1000))
eq(a/0.5, td(14))
eq(b/0.5, td(0, 120))
eq(a/7, td(1))
eq(b/10, td(0, 6))
eq(c/1000, td(0, 0, 1))
eq(a/10, td(0, 7*24*360))
eq(a/3600000, td(0, 0, 7*24*1000))
# Multiplication by float
us = td(microseconds=1)
eq((3*us) * 0.5, 2*us)
eq((5*us) * 0.5, 2*us)
eq(0.5 * (3*us), 2*us)
eq(0.5 * (5*us), 2*us)
eq((-3*us) * 0.5, -2*us)
eq((-5*us) * 0.5, -2*us)
# Division by int and float
eq((3*us) / 2, 2*us)
eq((5*us) / 2, 2*us)
eq((-3*us) / 2.0, -2*us)
eq((-5*us) / 2.0, -2*us)
eq((3*us) / -2, -2*us)
eq((5*us) / -2, -2*us)
eq((3*us) / -2.0, -2*us)
eq((5*us) / -2.0, -2*us)
for i in range(-10, 10):
eq((i*us/3)//us, round(i/3))
for i in range(-10, 10):
eq((i*us/-3)//us, round(i/-3))
def test_disallowed_computations(self):
a = timedelta(42)
@ -236,20 +276,19 @@ def test_disallowed_computations(self):
self.assertRaises(TypeError, lambda: i+a)
self.assertRaises(TypeError, lambda: i-a)
# Mul/div by float isn't supported.
x = 2.3
self.assertRaises(TypeError, lambda: a*x)
self.assertRaises(TypeError, lambda: x*a)
self.assertRaises(TypeError, lambda: a/x)
self.assertRaises(TypeError, lambda: x/a)
self.assertRaises(TypeError, lambda: a // x)
self.assertRaises(TypeError, lambda: x // a)
# Division of int by timedelta doesn't make sense.
# Division by zero doesn't make sense.
zero = 0
self.assertRaises(TypeError, lambda: zero // a)
self.assertRaises(ZeroDivisionError, lambda: a // zero)
self.assertRaises(ZeroDivisionError, lambda: a / zero)
self.assertRaises(ZeroDivisionError, lambda: a / 0.0)
@requires_IEEE_754
def test_disallowed_special(self):
a = timedelta(42)
self.assertRaises(ValueError, a.__mul__, NAN)
self.assertRaises(ValueError, a.__truediv__, NAN)
def test_basic_attributes(self):
days, seconds, us = 1, 7, 31
@ -410,6 +449,19 @@ def test_overflow(self):
self.assertRaises(OverflowError, lambda: -timedelta.max)
day = timedelta(1)
self.assertRaises(OverflowError, day.__mul__, 10**9)
self.assertRaises(OverflowError, day.__mul__, 1e9)
self.assertRaises(OverflowError, day.__truediv__, 1e-20)
self.assertRaises(OverflowError, day.__truediv__, 1e-10)
self.assertRaises(OverflowError, day.__truediv__, 9e-10)
@requires_IEEE_754
def _test_overflow_special(self):
day = timedelta(1)
self.assertRaises(OverflowError, day.__mul__, INF)
self.assertRaises(OverflowError, day.__mul__, -INF)
def test_microsecond_rounding(self):
td = timedelta
eq = self.assertEqual
@ -489,7 +541,7 @@ def test_division(self):
self.assertRaises(ZeroDivisionError, truediv, t, zerotd)
self.assertRaises(ZeroDivisionError, floordiv, t, zerotd)
self.assertRaises(TypeError, truediv, t, 2)
# self.assertRaises(TypeError, truediv, t, 2)
# note: floor division of a timedelta by an integer *is*
# currently permitted.

5
Misc/NEWS
View file

@ -398,6 +398,11 @@ C-API
Library
-------
- Issue #1289118: datetime.timedelta objects can now be multiplied by float
and divided by float and int objects. Results are rounded to the nearest
multiple of timedelta.resolution with ties resolved using round-half-to-even
method.
- Issue #7150: Raise OverflowError if the result of adding or subtracting
timedelta from date or datetime falls outside of the MINYEAR:MAXYEAR range.

113
Modules/datetimemodule.c
View file

@ -152,6 +152,25 @@ round_to_long(double x)
return (long)x;
}
/* Nearest integer to m / n for integers m and n. Half-integer results
* are rounded to even.
*/
static PyObject *
divide_nearest(PyObject *m, PyObject *n)
{
PyObject *result;
PyObject *temp;
temp = _PyLong_Divmod_Near(m, n);
if (temp == NULL)
return NULL;
result = PyTuple_GET_ITEM(temp, 0);
Py_INCREF(result);
Py_DECREF(temp);
return result;
}
/* ---------------------------------------------------------------------------
* General calendrical helper functions
*/
@ -1647,6 +1666,37 @@ multiply_int_timedelta(PyObject *intobj, PyDateTime_Delta *delta)
return result;
}
static PyObject *
multiply_float_timedelta(PyObject *floatobj, PyDateTime_Delta *delta)
{
PyObject *result = NULL;
PyObject *pyus_in = NULL, *temp, *pyus_out;
PyObject *ratio = NULL;
pyus_in = delta_to_microseconds(delta);
if (pyus_in == NULL)
return NULL;
ratio = PyObject_CallMethod(floatobj, "as_integer_ratio", NULL);
if (ratio == NULL)
goto error;
temp = PyNumber_Multiply(pyus_in, PyTuple_GET_ITEM(ratio, 0));
Py_DECREF(pyus_in);
pyus_in = NULL;
if (temp == NULL)
goto error;
pyus_out = divide_nearest(temp, PyTuple_GET_ITEM(ratio, 1));
Py_DECREF(temp);
if (pyus_out == NULL)
goto error;
result = microseconds_to_delta(pyus_out);
Py_DECREF(pyus_out);
error:
Py_XDECREF(pyus_in);
Py_XDECREF(ratio);
return result;
}
static PyObject *
divide_timedelta_int(PyDateTime_Delta *delta, PyObject *intobj)
{
@ -1714,6 +1764,55 @@ truedivide_timedelta_timedelta(PyDateTime_Delta *left, PyDateTime_Delta *right)
return result;
}
static PyObject *
truedivide_timedelta_float(PyDateTime_Delta *delta, PyObject *f)
{
PyObject *result = NULL;
PyObject *pyus_in = NULL, *temp, *pyus_out;
PyObject *ratio = NULL;
pyus_in = delta_to_microseconds(delta);
if (pyus_in == NULL)
return NULL;
ratio = PyObject_CallMethod(f, "as_integer_ratio", NULL);
if (ratio == NULL)
goto error;
temp = PyNumber_Multiply(pyus_in, PyTuple_GET_ITEM(ratio, 1));
Py_DECREF(pyus_in);
pyus_in = NULL;
if (temp == NULL)
goto error;
pyus_out = divide_nearest(temp, PyTuple_GET_ITEM(ratio, 0));
Py_DECREF(temp);
if (pyus_out == NULL)
goto error;
result = microseconds_to_delta(pyus_out);
Py_DECREF(pyus_out);
error:
Py_XDECREF(pyus_in);
Py_XDECREF(ratio);
return result;
}
static PyObject *
truedivide_timedelta_int(PyDateTime_Delta *delta, PyObject *i)
{
PyObject *result;
PyObject *pyus_in, *pyus_out;
pyus_in = delta_to_microseconds(delta);
if (pyus_in == NULL)
return NULL;
pyus_out = divide_nearest(pyus_in, i);
Py_DECREF(pyus_in);
if (pyus_out == NULL)
return NULL;
result = microseconds_to_delta(pyus_out);
Py_DECREF(pyus_out);
return result;
}
static PyObject *
delta_add(PyObject *left, PyObject *right)
{
@ -1838,10 +1937,16 @@ delta_multiply(PyObject *left, PyObject *right)
if (PyLong_Check(right))
result = multiply_int_timedelta(right,
(PyDateTime_Delta *) left);
else if (PyFloat_Check(right))
result = multiply_float_timedelta(right,
(PyDateTime_Delta *) left);
}
else if (PyLong_Check(left))
result = multiply_int_timedelta(left,
(PyDateTime_Delta *) right);
(PyDateTime_Delta *) right);
else if (PyFloat_Check(left))
result = multiply_float_timedelta(left,
(PyDateTime_Delta *) right);
if (result == Py_NotImplemented)
Py_INCREF(result);
@ -1880,6 +1985,12 @@ delta_truedivide(PyObject *left, PyObject *right)
result = truedivide_timedelta_timedelta(
(PyDateTime_Delta *)left,
(PyDateTime_Delta *)right);
else if (PyFloat_Check(right))
result = truedivide_timedelta_float(
(PyDateTime_Delta *)left, right);
else if (PyLong_Check(right))
result = truedivide_timedelta_int(
(PyDateTime_Delta *)left, right);
}
if (result == Py_NotImplemented)