On Mon, Dec 21, 2020 at 8:26 AM Paul Bryan
Wouldn't that still work if bool's __int__ returns 1?
Yes, there are ways you could accomplish the `sum(trues)` pattern other than making bool a subclass of int. But as Chris points out, the value of `1 == True == 1.0` is pretty fundamental to many other patterns also. And likewise, things being in sets by equality rather than identity is likewise fundamental. The change you suggest to make `True != 1` "breaks the world".
On Mon, 2020-12-21 at 03:09 -0500, David Mertz wrote:
I sure hope this never happens! It would break millions of working lines and kill a common useful pattern.
ntrue = sum(this == that for this, that in items)
-100.
On Mon, Dec 21, 2020, 3:00 AM Paul Bryan
wrote: I know this has come up in the past.
Could the consensus have changed regarding bool's inheritance from int?
This is not intuitive (to me), and recently bit me as a bug:
Python 3.9.1 (default, Dec 13 2020, 11:55:53)
[GCC 10.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
{1,True}
{1}
I've worked around it by storing tuple(type, value) in the set, which is fugly. Yes, I need mixed types in the set, and I'm using the set for efficient lookup.
A contrived example I dreamed-up, which I also find non-intuitive:
x = {}
x[True] = 1
x
{True: 1}
x[1] = 1
x
{True: 1}
Maybe a wish list item for Python 4.0?
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