On 4/26/2012 13:45, Adam Skutt wrote:
On Apr 26, 1:48 am, John Nagle<na...@animats.com> wrote:
On 4/25/2012 5:01 PM, Steven D'Aprano wrote:
On Wed, 25 Apr 2012 13:49:24 -0700, Adam Skutt wrote:
Though, maybe it's better to use a different keyword than 'is' though,
due to the plain English
connotations of the term; I like 'sameobj' personally, for whatever
little it matters. Really, I think taking away the 'is' operator
altogether is better, so the only way to test identity is:
id(x) == id(y)
Four reasons why that's a bad idea:
1) The "is" operator is fast, because it can be implemented directly by
the interpreter as a simple pointer comparison (or equivalent).
This assumes that everything is, internally, an object. In CPython,
that's the case, because Python is a naive interpreter and everything,
including numbers, is "boxed". That's not true of PyPy or Shed Skin.
So does "is" have to force the creation of a temporary boxed object?
That's what C# does AFAIK. Java defines '==' as value comparison for
primitives and '==' as identity comparison for objects, but I don't
exactly know how one would do that in Python.
Why should we take from Java one of its worst misfeatures and disfigure
Python for life?
a==b compares references while a.equals(b) compares values. Really???
Come on...
Python's way is much much cleaner.
Kiuhnm
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