[Python-ideas] range

[Bruce Leban]

On Thu, Feb 21, 2013 at 5:50 AM, Yuval Greenfield <ubershmekel at gmail.com>wrote:

> On Thu, Feb 21, 2013 at 3:35 PM, Wolfgang Maier <
> wolfgang.maier at biologie.uni-freiburg.de> wrote:
>
>> a = range(1,10)
>> b = range(5,12)
>> intersect = a & b     # equivalent to intersect = range(5,10)
>> merge = a | b         # equivalent to merge = range(1,12)
>>
>> ...

>  this whole idea is reminiscent, of course, of what's implemented for sets
>> already, so like there you could think of
>> intersect = a & b as shorthand for intersect = a.intersection(b)
>>
>> I think each operation you implement can have a lot of different bikeshed
> details. Since these are all very simple to begin with, it's better to not
> burden the language and just let users implement whatever it is they need.
>
>
Ignoring performance issues, imagine instead a sorted set class that you
could add ranges to (or remove them). Well, actually it's trivial to
convert a range to a set; the interesting problem is performance. You could
save the range parts unexpanded so you could add huge ranges and you could
also support infinite ranges (itertools.count).

I suggest this because once you consider doing the first set of operations,
like r1 & r2, it's quite natural for someone to want

some_non_unlucky_integers = range(100) - [13]

The idea of a sorted set class is, of course, not original. See for example
http://stutzbachenterprises.com/blist/sortedset.html. If SortedSet isn't in
the stdlib, I can't imagine this enhancement being either.

--- Bruce
Latest blog post: Alice's Puzzle Page http://www.vroospeak.com
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