[Python-ideas] [Python-Dev] The Case Against Floating Point ==

Jim Jewett jimjjewett at gmail.com
Tue Mar 18 23:42:28 CET 2008


On 3/14/08, Imri Goldberg <lorgandon at gmail.com> wrote:

> Alright, I agree it's a good idea to drop the proposal to changing
>  floating point == into an epsilon compare.
>  What about issuing a warning though?
>  Consider the following course of action. It is the one with the least
>  changes:

>  == for regular floating point numbers now issues a warning, but still
>  works. This warning might be turned off. All other operators are left
>  unchanged.

If you change ==, you should really change !=, and probably the other
comparisons as well.

I suspect what you really want is a warning on any usage of a floating
point.  And I'm only half-joking.  Comparison (or arithmetic) with
other floats adds error.  Comparison (or arithmetic) with ints is
*usually* a bug (unless one of the operands is a constant that someone
was too lazy to write correctly).

-jJ



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