diff options
| -rw-r--r-- | Doc/library/random.rst | 13 | ||||
| -rw-r--r-- | Lib/random.py | 52 | ||||
| -rw-r--r-- | Lib/test/test_random.py | 80 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2022-02-03-12-07-41.bpo-46624.f_Qqh0.rst | 1 |
4 files changed, 95 insertions, 51 deletions
diff --git a/Doc/library/random.rst b/Doc/library/random.rst index 36f232d..da4a4f6 100644 --- a/Doc/library/random.rst +++ b/Doc/library/random.rst @@ -135,10 +135,15 @@ Functions for integers values. Formerly it used a style like ``int(random()*n)`` which could produce slightly uneven distributions. - .. versionchanged:: 3.11 - Automatic conversion of non-integer types is no longer supported. - Calls such as ``randrange(10.0)`` and ``randrange(Fraction(10, 1))`` - now raise a :exc:`TypeError`. + .. deprecated:: 3.10 + The automatic conversion of non-integer types to equivalent integers is + deprecated. Currently ``randrange(10.0)`` is losslessly converted to + ``randrange(10)``. In the future, this will raise a :exc:`TypeError`. + + .. deprecated:: 3.10 + The exception raised for non-integral values such as ``randrange(10.5)`` + or ``randrange('10')`` will be changed from :exc:`ValueError` to + :exc:`TypeError`. .. function:: randint(a, b) diff --git a/Lib/random.py b/Lib/random.py index e8bc941..6d7b617 100644 --- a/Lib/random.py +++ b/Lib/random.py @@ -282,17 +282,27 @@ class Random(_random.Random): ## -------------------- integer methods ------------------- def randrange(self, start, stop=None, step=_ONE): - """Choose a random item from range(stop) or range(start, stop[, step]). + """Choose a random item from range(start, stop[, step]). - Roughly equivalent to ``choice(range(start, stop, step))`` - but supports arbitrarily large ranges and is optimized - for common cases. + This fixes the problem with randint() which includes the + endpoint; in Python this is usually not what you want. """ # This code is a bit messy to make it fast for the # common case while still doing adequate error checking. - istart = _index(start) + try: + istart = _index(start) + except TypeError: + istart = int(start) + if istart != start: + _warn('randrange() will raise TypeError in the future', + DeprecationWarning, 2) + raise ValueError("non-integer arg 1 for randrange()") + _warn('non-integer arguments to randrange() have been deprecated ' + 'since Python 3.10 and will be removed in a subsequent ' + 'version', + DeprecationWarning, 2) if stop is None: # We don't check for "step != 1" because it hasn't been # type checked and converted to an integer yet. @@ -302,15 +312,37 @@ class Random(_random.Random): return self._randbelow(istart) raise ValueError("empty range for randrange()") - # Stop argument supplied. - istop = _index(stop) + # stop argument supplied. + try: + istop = _index(stop) + except TypeError: + istop = int(stop) + if istop != stop: + _warn('randrange() will raise TypeError in the future', + DeprecationWarning, 2) + raise ValueError("non-integer stop for randrange()") + _warn('non-integer arguments to randrange() have been deprecated ' + 'since Python 3.10 and will be removed in a subsequent ' + 'version', + DeprecationWarning, 2) width = istop - istart - istep = _index(step) + try: + istep = _index(step) + except TypeError: + istep = int(step) + if istep != step: + _warn('randrange() will raise TypeError in the future', + DeprecationWarning, 2) + raise ValueError("non-integer step for randrange()") + _warn('non-integer arguments to randrange() have been deprecated ' + 'since Python 3.10 and will be removed in a subsequent ' + 'version', + DeprecationWarning, 2) # Fast path. if istep == 1: if width > 0: return istart + self._randbelow(width) - raise ValueError(f"empty range in randrange({start}, {stop}, {step})") + raise ValueError("empty range for randrange() (%d, %d, %d)" % (istart, istop, width)) # Non-unit step argument supplied. if istep > 0: @@ -320,7 +352,7 @@ class Random(_random.Random): else: raise ValueError("zero step for randrange()") if n <= 0: - raise ValueError(f"empty range in randrange({start}, {stop}, {step})") + raise ValueError("empty range for randrange()") return istart + istep * self._randbelow(n) def randint(self, a, b): diff --git a/Lib/test/test_random.py b/Lib/test/test_random.py index f980c5b..5b066d2 100644 --- a/Lib/test/test_random.py +++ b/Lib/test/test_random.py @@ -481,44 +481,50 @@ class SystemRandom_TestBasicOps(TestBasicOps, unittest.TestCase): self.assertEqual(rint, 0) def test_randrange_errors(self): - raises_value_error = partial(self.assertRaises, ValueError, self.gen.randrange) - raises_type_error = partial(self.assertRaises, TypeError, self.gen.randrange) - + raises = partial(self.assertRaises, ValueError, self.gen.randrange) # Empty range - raises_value_error(3, 3) - raises_value_error(-721) - raises_value_error(0, 100, -12) - - # Zero step - raises_value_error(0, 42, 0) - raises_type_error(0, 42, 0.0) - raises_type_error(0, 0, 0.0) - - # Non-integer stop - raises_type_error(3.14159) - raises_type_error(3.0) - raises_type_error(Fraction(3, 1)) - raises_type_error('3') - raises_type_error(0, 2.71827) - raises_type_error(0, 2.0) - raises_type_error(0, Fraction(2, 1)) - raises_type_error(0, '2') - raises_type_error(0, 2.71827, 2) - - # Non-integer start - raises_type_error(2.71827, 5) - raises_type_error(2.0, 5) - raises_type_error(Fraction(2, 1), 5) - raises_type_error('2', 5) - raises_type_error(2.71827, 5, 2) - - # Non-integer step - raises_type_error(0, 42, 3.14159) - raises_type_error(0, 42, 3.0) - raises_type_error(0, 42, Fraction(3, 1)) - raises_type_error(0, 42, '3') - raises_type_error(0, 42, 1.0) - raises_type_error(0, 0, 1.0) + raises(3, 3) + raises(-721) + raises(0, 100, -12) + # Non-integer start/stop + self.assertWarns(DeprecationWarning, raises, 3.14159) + self.assertWarns(DeprecationWarning, self.gen.randrange, 3.0) + self.assertWarns(DeprecationWarning, self.gen.randrange, Fraction(3, 1)) + self.assertWarns(DeprecationWarning, raises, '3') + self.assertWarns(DeprecationWarning, raises, 0, 2.71828) + self.assertWarns(DeprecationWarning, self.gen.randrange, 0, 2.0) + self.assertWarns(DeprecationWarning, self.gen.randrange, 0, Fraction(2, 1)) + self.assertWarns(DeprecationWarning, raises, 0, '2') + # Zero and non-integer step + raises(0, 42, 0) + self.assertWarns(DeprecationWarning, raises, 0, 42, 0.0) + self.assertWarns(DeprecationWarning, raises, 0, 0, 0.0) + self.assertWarns(DeprecationWarning, raises, 0, 42, 3.14159) + self.assertWarns(DeprecationWarning, self.gen.randrange, 0, 42, 3.0) + self.assertWarns(DeprecationWarning, self.gen.randrange, 0, 42, Fraction(3, 1)) + self.assertWarns(DeprecationWarning, raises, 0, 42, '3') + self.assertWarns(DeprecationWarning, self.gen.randrange, 0, 42, 1.0) + self.assertWarns(DeprecationWarning, raises, 0, 0, 1.0) + + def test_randrange_argument_handling(self): + randrange = self.gen.randrange + with self.assertWarns(DeprecationWarning): + randrange(10.0, 20, 2) + with self.assertWarns(DeprecationWarning): + randrange(10, 20.0, 2) + with self.assertWarns(DeprecationWarning): + randrange(10, 20, 1.0) + with self.assertWarns(DeprecationWarning): + randrange(10, 20, 2.0) + with self.assertWarns(DeprecationWarning): + with self.assertRaises(ValueError): + randrange(10.5) + with self.assertWarns(DeprecationWarning): + with self.assertRaises(ValueError): + randrange(10, 20.5) + with self.assertWarns(DeprecationWarning): + with self.assertRaises(ValueError): + randrange(10, 20, 1.5) def test_randrange_step(self): # bpo-42772: When stop is None, the step argument was being ignored. diff --git a/Misc/NEWS.d/next/Library/2022-02-03-12-07-41.bpo-46624.f_Qqh0.rst b/Misc/NEWS.d/next/Library/2022-02-03-12-07-41.bpo-46624.f_Qqh0.rst new file mode 100644 index 0000000..b0203b9 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2022-02-03-12-07-41.bpo-46624.f_Qqh0.rst @@ -0,0 +1 @@ +Restore support for non-integer arguments of :func:`random.randrange` and :func:`random.randint`. |