Fwd: Add math.iszero() and math.isequal()?
something went weird with the google groups mirror of this list -- sorry if
this lands twice.
-Chris
---------- Forwarded message ----------
From: Chris Barker
See PEP 485, which appears to be still a draft: https://www.python.org/dev/peps/pep-0485/
It's been approved, and it's "just" waiting for me to implement the code and get it reviewed, etc. I've been much sidetracked, but hoping to get to in the next couple days.... iszero = lambda x: hash(x) == hash(0)
isequal = lambda a, b: hash(a) == hash(b)
Clearly these are trivial functions (but perphaps math experts could provide better implementations; I'm not proposing the implementations shown, just the functions however they are implemented).
I'm not familiar with how hashing works for floats, but I can't image this would even work -- == an !== work for floats, then just don't test what people most often want :-) Anyway, see the PEP, and the quite long and drawn out discussion on this list a couple months back. -CHB
It seems that not everyone is aware of the issues regarding comparing floats for equality and so I still see code that compares floats using == or !=.
If these functions were in the math module it would be convenient (since I find I need them in most non-trivial programs), but also provide a place to document that they should be used rather than == or != for floats. (I guess a similar argument might apply to the cmath module?)
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-- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception Chris.Barker@noaa.gov -- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception Chris.Barker@noaa.gov
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Chris Barker