diff options
Diffstat (limited to 'Doc/whatsnew')
| -rw-r--r-- | Doc/whatsnew/3.1.rst | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/Doc/whatsnew/3.1.rst b/Doc/whatsnew/3.1.rst index c1972ec..41973ac 100644 --- a/Doc/whatsnew/3.1.rst +++ b/Doc/whatsnew/3.1.rst @@ -155,7 +155,7 @@ Some smaller changes made to the core Python language are: The significance is easily seen with a number like ``1.1`` which does not have an exact equivalent in binary floating point. Since there is no exact - equivalent, an expression like ``float("1.1")`` evaluates to the nearest + equivalent, an expression like ``float('1.1')`` evaluates to the nearest representable value which is ``0x1.199999999999ap+0`` in hex or ``1.100000000000000088817841970012523233890533447265625`` in decimal. That nearest value was and still is used in subsequent floating point @@ -163,16 +163,16 @@ Some smaller changes made to the core Python language are: What is new is how the number gets displayed. Formerly, Python used a simple approach. The value of ``repr(1.1)`` was computed as ``format(1.1, - '.17g')`` which evaluates to ``'1.1000000000000001'``. The advantage of + '.17g')`` which evaluated to ``'1.1000000000000001'``. The advantage of using 17 digits was that it relied on IEEE-754 guarantees to assure that ``eval(repr(1.1))`` would round-trip exactly to its original value. The disadvantage is that many people found the output to be confusing (mistaking intrinsic limitations of binary floating point representation as being a problem with Python itself). - The new algorithm for ``repr(1.1)`` is smarter and returns ``1.1``. + The new algorithm for ``repr(1.1)`` is smarter and returns ``'1.1'``. Effectively, it searches all equivalent string representations (ones that - get stored as the same underlying float value) and returns the shortest + get stored with the same underlying float value) and returns the shortest representation. The new algorithm tends to emit cleaner representations when possible, but |