bpo-33073: Adding as_integer_ratio to ints.

Doc/library/stdtypes.rst

@@ -539,6 +539,14 @@ class`. In addition, it provides a few more methods:
 
  .. versionadded:: 3.2
 
+.. method:: int.as_integer_ratio()
+
+ Return a pair of integers whose ratio is exactly equal to the original
+ integer and with a positive denominator. The integer ratio of integers
+ (whole numbers) is always the integer as the numerator and ``1`` as the
+ denominator.
+
+ .. versionadded:: 3.8
 
 Additional Methods on Float
 ---------------------------

Doc/whatsnew/3.8.rst

@@ -91,6 +91,10 @@ Other Language Changes
  was lifted.
  (Contributed by Serhiy Storchaka in :issue:`32489`.)
 
+* The ``int`` type now has a new ``as_integer_ratio`` method compatible
+ with the existing ``float.as_integer_ratio`` method.
+ (Contributed by Lisa Roach in :issue:`33073`.)
+
 * Added support of ``\N{name}`` escapes in :mod:`regular expressions <re>`.
  (Contributed by Jonathan Eunice and Serhiy Storchaka in :issue:`30688`.)
 

Lib/test/test_doctest.py

@@ -665,7 +665,7 @@ def non_Python_modules(): r"""
  True
  >>> real_tests = [t for t in tests if len(t.examples) > 0]
  >>> len(real_tests) # objects that actually have doctests
-8
+9
  >>> for t in real_tests:
  ... print('{} {}'.format(len(t.examples), t.name))
  ...
@@ -675,6 +675,7 @@ def non_Python_modules(): r"""
  2 builtins.float.hex
  1 builtins.hex
  1 builtins.int
+ 3 builtins.int.as_integer_ratio
  2 builtins.int.bit_length
  1 builtins.oct
 

Lib/test/test_long.py

@@ -3,6 +3,7 @@
 
 import sys
 
+import enum
 import random
 import math
 import array
@@ -1349,6 +1350,37 @@ def test_shift_bool(self):
  self.assertEqual(type(value << shift), int)
  self.assertEqual(type(value >> shift), int)
 
+ def test_as_integer_ratio(self):
+ tests = [10, 0, -10, 1]
+ for value in tests:
+ numerator, denominator = value.as_integer_ratio()
+ self.assertEqual((numerator, denominator), (value, 1))
+ self.assertIsInstance(numerator, int)
+ self.assertIsInstance(denominator, int)
+
+ def test_as_integer_ratio_maxint(self):
+ x = sys.maxsize + 1
+ self.assertEqual(x.as_integer_ratio()[0], x)
+
+ def test_as_integer_ratio_bool(self):
+ self.assertEqual(True.as_integer_ratio(), (1, 1))
+ self.assertEqual(False.as_integer_ratio(), (0, 1))
+ self.assertEqual(type(True.as_integer_ratio()[0]), int)
+ self.assertEqual(type(False.as_integer_ratio()[0]), int)
+
+ def test_as_integer_ratio_int_enum(self):
+ class Foo(enum.IntEnum):
+ X = 42
+ self.assertEqual(Foo.X.as_integer_ratio(), (42, 1))
+ self.assertEqual(type(Foo.X.as_integer_ratio()[0]), int)
+
+ def test_as_integer_ratio_int_flag(self):
+ class Foo(enum.IntFlag):
+ R = 1 << 2
+ self.assertEqual(Foo.R.as_integer_ratio(), (4, 1))
+ self.assertEqual(type(Foo.R.as_integer_ratio()[0]), int)
+
+
 
 if __name__ == "__main__":
  unittest.main()

Misc/ACKS

@@ -1347,6 +1347,7 @@ Juan M. Bello Rivas
 Mohd Sanad Zaki Rizvi
 Davide Rizzo
 Anthony Roach
+Lisa Roach
 Carl Robben
 Ben Roberts
 Mark Roberts

Misc/NEWS.d/next/Core and Builtins/2018-08-12-16-03-58.bpo-33073.XWu1Jh.rst

@@ -0,0 +1 @@
+Added as_integer_ratio to ints to make them more interoperable with floats.

Objects/longobject.c

@@ -5260,6 +5260,36 @@ long_is_finite(PyObject *v)
 }
 #endif
 
+/*[clinic input]
+int.as_integer_ratio
+
+Return integer ratio.
+
+Return a pair of integers, whose ratio is exactly equal to the original int
+and with a positive denominator.
+
+>>> (10).as_integer_ratio()
+(10, 1)
+>>> (-10).as_integer_ratio()
+(-10, 1)
+>>> (0).as_integer_ratio()
+(0, 1)
+[clinic start generated code]*/
+
+static PyObject *
+int_as_integer_ratio_impl(PyObject *self)
+/*[clinic end generated code: output=e60803ae1cc8621a input=55ce3058e15de393]*/
+{
+ if PyLong_CheckExact(self) {
+ return PyTuple_Pack(2, self, _PyLong_One);
+ } else {
+ PyObject *numerator = _PyLong_Copy(self);
+ PyObject *ratio_tuple = PyTuple_Pack(2, numerator, _PyLong_One);
+ Py_DECREF(numerator);
+ return ratio_tuple;
+ }
+}
+
 /*[clinic input]
 int.to_bytes
 
@@ -5392,6 +5422,7 @@ static PyMethodDef long_methods[] = {
 #endif
  INT_TO_BYTES_METHODDEF
  INT_FROM_BYTES_METHODDEF
+ INT_AS_INTEGER_RATIO_METHODDEF
  {"__trunc__", long_long_meth, METH_NOARGS,
  "Truncating an Integral returns itself."},
  {"__floor__", long_long_meth, METH_NOARGS,