Steve Jorgensen wrote:
> I am purposefully proposing this for slices as opposed to ranges because it
> is about
> the bounds of the slices, not the items in synthetic sequences. Also, slices
> can refer to
> any type of value, not just integers.
> Presumably, these operations would raise exceptions when used with slices
> that have
> step values other than None. Alternatively, those could
> hypothetically be valid in restricted cases such as when all properties are
> either int or
> Fraction types. Probably better to have them be simply unsupported though.
> a in b # True if <a> is fully contained within <b>
> a.intersects(b) # True if any value could be within both <a> and <b>
> a & b # Intersection of <a> and <b> or None if no intersection
> a | b # Union of <a> and <b> or Exception if neither contiguous nor
> overlapping.
>
> Also, it might be nice to be able to test whether a non-slice value falls
> within the
> slice's bounds. This would be using x in s as a shorthand for s.start
> <= x < s.end. Again, this is different than asking whether a value is "in" a
> range because a rage is a sequence of discrete integers whereas a slice
> represents a
> possibly continuous range of any kind of value to which magnitude is
> applicable.
> slice(1, 2) in (0, 3)
> # => True because 1 >= 0 and 2 <= 3
>
> slice(0.5, 1.5) in slice(0, 2)
> # => True because 0.5 >= 1.5 and 0.5 < 2
>
> 1 in (0, 3)
> # => True because 0 <= 1 < 3
>
> 'Joe' in slice('Alice', 'Riley')
> # => True because 'Alice' <= 'Joe' < 'Riley'
>
> slice(1.1, 5.9).intersects(slice(2, 10.5))
> # => True because either...
> # 1.1 <= 2 < 5.9 or
> # 1.1 < 10.5 < 5.5 or
> # 2 <= 1.1 < 10.5 or
> # 2 < 5.9 < 10.5
>
> slice(5.5, 15.5) & slice(10.25, 20.25)
> # => slice(10.25, 15.5)
>
> slice(5.5, 15.5) | slice(10.25, 20.25)
> # => slice(5.5, 20.25)
>
> slice('abc', 'fff') & slice('eee', 'xyz')
> # => slice('fff', 'eee')
I notice I made a couple of subtle mistakes in the above. All the more reason
to implement these concepts correctly as standard. :)
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