[Python-Dev] Why don't range and xrange threat floats as floats?

Leif Walsh leif.walsh at gmail.com
Wed Nov 5 19:38:45 CET 2008

On Wed, Nov 5, 2008 at 1:26 PM, L V <somelauw at yahoo.com> wrote:
> Why don't range and xrange threat floats as floats?
> Is there any good reason range and xrange don't threat floats as floats but
> as integers?
> When I enter float arguments in a range, the floats are treated as integers.
> (+ some warning)
> This is how I think it should work:
>>>>range(0, 1, 0.1)
> [0.0, 0.10000000000000001, 0.20000000000000001, 0.29999999999999999,
> 0.40000000000000002, 0.5, 0.59999999999999998, 0.69999999999999996,
> 0.80000000000000004, 0.90000000000000002]
> I got these results by:
>>>>[x/10. for x in xrange(10)]
> I'm not looking for alternatives, just for the reason that it works this
> way.

This seems like a question to be asked on python-list, not python-dev.

In any case, my best guess is that it's because of what you just
showed, that the functionality you want is there already if you use a
generator expression.  There isn't much reason to make (x)range more
complicated by letting it accept floats, when you can just scale the
range you actually want up to some integral skip value, call range,
and then scale it back down.


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