Add subset and superset methods to Sage's finite sets (Set_object_enumerated)

[nthiery]

From the doc::

            sage: X = Set([1,3,5])
            sage: Y = Set([0,1,2,3,5,7])
            sage: X.issubset(Y)
            True
            sage: Y.issupset(X)
            True

Component: combinatorics

Author: Nicolas M. Thiéry

Reviewer: Jason Bandlow

Merged: sage-4.7.1.alpha0

Issue created by migration from https://trac.sagemath.org/ticket/10938

[jbandlow]

comment:1

Hi Nicolas!

One point: I think these should be called is_subset and is_superset for consistency with the most of the other is_* methods throughout sage. I realize that Python sets use issubset and issuperset, but I think the underscore makes the methods easier to read in the long lists that tend to come up with tab completion on sage objects. What do you think?

[nthiery]

comment:2

Hi Jason!

Replying to @jbandlow:

One point: I think these should be called is_subset and is_superset for consistency with the most of the other is_* methods throughout sage. I realize that Python sets use issubset and issuperset, but I think the underscore makes the methods easier to read in the long lists that tend to come up with tab completion on sage objects. What do you think?

Yeah, that's annoying. However, my feeling is that compatibility with
Python's sets should have priority, in particular so that one could
use them a bit more interchangeably (e.g. plug a Sage Set in code that
expects a sage set).

Cheers,
Nicolas

[novoselt]

comment:3

Would it be acceptable to have both options?

It would be nice also to have a better Hg-comment in the patch ;-)

[nthiery]

comment:4

Attachment: trac_10938-Set-issubset_issuperset-nt.patch.gz

Hi Andrei,

Replying to @novoselt:

Would it be acceptable to have both options?

You are welcome to raise the question on sage-devel. However, that
risks to be a source of confusion in the long run. Typically, a
specific sage set might forget to override both issubset and is_subset
when implementing e.g. a faster method for testing containment. In any cases,
I would tend to leave that to a subsequent patch.

It would be nice also to have a better Hg-comment in the patch ;-)

Oops, fixed. Thanks!

[nthiery]

comment:5

Hi Andrei, Jason!

Could any of you finish the review of this patch to get it in 4.7 and out of the Sage-Combinat queue? (the poset patch depends on it)

Thanks!
Nicolas

[jbandlow]

Reviewer: Jason Bandlow

[jbandlow]

comment:6

Ok, I agree that compatibility with Python is the way to go. The patch looks good to me... positive review.

[nthiery]

comment:7

Replying to @jbandlow:

Ok, I agree that compatibility with Python is the way to go. The patch looks good to me... positive review.

Thanks Jason!

[jdemeyer]

Merged: sage-4.7.1.alpha0