Manually merge r68095,68186,68187,68188,68190 from 2.6 branch.
diff --git a/Doc/library/decimal.rst b/Doc/library/decimal.rst
index 73de358..e793a45 100644
--- a/Doc/library/decimal.rst
+++ b/Doc/library/decimal.rst
@@ -1923,13 +1923,14 @@
def float_to_decimal(f):
"Convert a floating point number to a Decimal with no loss of information"
n, d = f.as_integer_ratio()
- with localcontext() as ctx:
- ctx.traps[Inexact] = True
- while True:
- try:
- return Decimal(n) / Decimal(d)
- except Inexact:
- ctx.prec += 1
+ numerator, denominator = Decimal(n), Decimal(d)
+ ctx = Context(prec=60)
+ result = ctx.divide(numerator, denominator)
+ while ctx.flags[Inexact]:
+ ctx.flags[Inexact] = False
+ ctx.prec *= 2
+ result = ctx.divide(numerator, denominator)
+ return result
.. doctest::
diff --git a/Lib/fractions.py b/Lib/fractions.py
index 4adb184..446ad8e 100755
--- a/Lib/fractions.py
+++ b/Lib/fractions.py
@@ -111,7 +111,7 @@
"""
if isinstance(f, numbers.Integral):
- f = float(f)
+ return cls(f)
elif not isinstance(f, float):
raise TypeError("%s.from_float() only takes floats, not %r (%s)" %
(cls.__name__, f, type(f).__name__))
diff --git a/Lib/heapq.py b/Lib/heapq.py
index 0a83b76..c13d650 100644
--- a/Lib/heapq.py
+++ b/Lib/heapq.py
@@ -354,6 +354,10 @@
Equivalent to: sorted(iterable, key=key)[:n]
"""
+ if key is None:
+ it = izip(iterable, count()) # decorate
+ result = _nsmallest(n, it)
+ return map(itemgetter(0), result) # undecorate
in1, in2 = tee(iterable)
it = izip(imap(key, in1), count(), in2) # decorate
result = _nsmallest(n, it)
@@ -365,6 +369,10 @@
Equivalent to: sorted(iterable, key=key, reverse=True)[:n]
"""
+ if key is None:
+ it = izip(iterable, imap(neg, count())) # decorate
+ result = _nlargest(n, it)
+ return map(itemgetter(0), result) # undecorate
in1, in2 = tee(iterable)
it = izip(imap(key, in1), imap(neg, count()), in2) # decorate
result = _nlargest(n, it)
diff --git a/Lib/test/test_fractions.py b/Lib/test/test_fractions.py
index 979fef7..a6c3c32 100644
--- a/Lib/test/test_fractions.py
+++ b/Lib/test/test_fractions.py
@@ -139,6 +139,8 @@
def testFromFloat(self):
self.assertRaises(TypeError, F.from_float, 3+4j)
self.assertEquals((10, 1), _components(F.from_float(10)))
+ bigint = 1234567890123456789
+ self.assertEquals((bigint, 1), _components(F.from_float(bigint)))
self.assertEquals((0, 1), _components(F.from_float(-0.0)))
self.assertEquals((10, 1), _components(F.from_float(10.0)))
self.assertEquals((-5, 2), _components(F.from_float(-2.5)))
diff --git a/Misc/NEWS b/Misc/NEWS
index 02a7df0..078824e9 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -127,6 +127,12 @@
- Issue #4646: distutils was choking on empty options arg in the setup
function. Original patch by Thomas Heller.
+- Fractions.from_float() no longer loses precision for integers too big to
+ cast as floats.
+
+- Issue 4790: The nsmallest() and nlargest() functions in the heapq module
+ did unnecessary work in the common case where no key function was specified.
+
- Issue #3767: Convert Tk object to string in tkColorChooser.
- Issue #3248: Allow placing ScrolledText in a PanedWindow.