PEP 238 (revised) (same as above, with typo fixed)

Chris Barker chrishbarker at home.net
Fri Jul 27 21:57:50 CEST 2001


oops, typo below:

Chris Barker wrote:
> 
> > Semantics of Floor Division
> >
> >     Floor division will be implemented in all the Python numeric
> >     types, and will have the semantics of
> >
> >         a // b == floor(a/b)
> >
> >     except that the type of a//b will be the type a and b will be
> >     coerced into.  Specifically, if a and b are of the same type, a//b
> >     will be of that type too.
> 
> so:
> 
> 3//2 == 1
> 
> 3.0//2.0 == 1.0
> 
> 3.0//2 == 1.0
> 
> so if I want to use the result as an index, I'll need to use:
> 
> int(x/y)
should be: int(x//y)  : the fact that I made that typo does tell me
something about how likely I am to make that kind of typ in code...Oh
Oh!
 
> kind of like I now use:
> 
> int(floor(x/y))
> 
> What I don't get, is why // couldn't return an integer always? It will
> always have an integral value. I suppose one problem is that the range
> of integers that a float (C double) can handle is larger than a 32 bit
> integer can hold. This could be solved in the future with int/long
> unification, what will be the behaviour then?

You know, given that I have to use the int() typecast anyway, the //
operator is seeming to be less and less useful. When I want to do floor
division, it is VERY frequently so that I can get an index! IF we define
Python to always do a floor(), rather than a round() when int() is
called, I don't need the // or the floor()

-Chris


-- 
Christopher Barker,
Ph.D.                                                           
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