diff --git a/Doc/whatsnew/2.7.rst b/Doc/whatsnew/2.7.rst index 92fedb7cf4d..dd53f387b18 100644 --- a/Doc/whatsnew/2.7.rst +++ b/Doc/whatsnew/2.7.rst @@ -121,6 +121,31 @@ Some smaller changes made to the core Python language are: (Contributed by Fredrik Johansson and Victor Stinner; :issue:`3439`.) +* Conversions from long integers and regular integers to floating + point now round differently, returning the floating-point number + closest to the number. This doesn't matter for small integers that + can be converted exactly, but for large numbers that will + unavoidably lose precision, Python 2.7 will now approximate more + closely. For example, Python 2.6 computed the following:: + + >>> n = 295147905179352891391 + >>> float(n) + 2.9514790517935283e+20 + >>> n - long(float(n)) + 65535L + + Python 2.7's floating-point result is larger, but much closer to the + true value:: + + >>> n = 295147905179352891391 + >>> float(n) + 2.9514790517935289e+20 + >>> n-long(float(n) + ... ) + -1L + + (Implemented by Mark Dickinson; :issue:`3166`.) + * The :class:`bytearray` type's :meth:`translate` method will now accept ``None`` as its first argument. (Fixed by Georg Brandl; :issue:`4759`.) @@ -298,6 +323,10 @@ changes, or look through the Subversion logs for all the details. ``Decimal('0.1000000000000000055511151231257827021181583404541015625')``. (Implemented by Raymond Hettinger; :issue:`4796`.) +* The :class:`Fraction` class will now accept two rational numbers + as arguments to its constructor. + (Implemented by Mark Dickinson; :issue:`5812`.) + * New function: the :mod:`gc` module's :func:`is_tracked` returns true if a given instance is tracked by the garbage collector, false otherwise. (Contributed by Antoine Pitrou; :issue:`4688`.) @@ -561,6 +590,10 @@ Changes to Python's build process and to the C API include: is particularly useful for asynchronous IO operations. (Contributed by Kristjan Valur Jonsson; :issue:`4293`.) +* Global symbols defined by the :mod:`ctypes` module are now prefixed + with ``Py`, or with ``_ctypes``. (Implemented by Thomas + Heller; :issue:`3102`.) + * The :program:`configure` script now checks for floating-point rounding bugs on certain 32-bit Intel chips and defines a :cmacro:`X87_DOUBLE_ROUNDING` preprocessor definition. No code currently uses this definition, @@ -599,10 +632,10 @@ Other Changes and Fixes * When importing a module from a :file:`.pyc` or :file:`.pyo` file with an existing :file:`.py` counterpart, the :attr:`co_filename` - attributes of all code objects if the original filename is obsolete, - which can happen if the file has been renamed, moved, or is accessed - through different paths. (Patch by Ziga Seilnacht and Jean-Paul - Calderone; :issue:`1180193`.) + attributes of the resulting code objects are overwritten when the + original filename is obsolete. This can happen if the file has been + renamed, moved, or is accessed through different paths. (Patch by + Ziga Seilnacht and Jean-Paul Calderone; :issue:`1180193`.) * The :file:`regrtest.py` script now takes a :option:`--randseed=` switch that takes an integer that will be used as the random seed