Set should implement union, intersection, difference and symmetric difference.

Question

Set should implement union, intersection, difference and symmetric difference.

morrisonlevi opened this issue 12 years ago · 10 comments

These would be useful for people who are interested in using sets for normal set operations instead of simply storing a bunch of unique values.

Answer 1 · 2012-11-29T19:02:56.000Z

I totally agree ... are you also going to add Complements , Cartesian product and ability to check & get Subsets

Answer 2 · 2012-11-29T19:07:49.000Z

I will definitely add the check for sub-sets. I could probably do a Complement as well.

I'm not sure how to represent the result of the Cartesian product, so that one would take some designing and maybe some new structures.

Answer 3 · 2012-11-29T19:17:42.000Z

I agree about Cartesian product, Another interesting set feature would be Power Sets, The only issue would be performance with large sets but this can be managed with fixed min & max length or introduction of fixed length ....

Answer 4 · 2012-12-03T00:14:31.000Z

A relative complement will be easy to implement. Not sure if representing an absolute complement is worthwhile or helpful in a language like PHP.

Answer 5 · 2012-12-03T07:55:37.000Z

@morrisonlevi Yes, go with the relative complement. That's the only real complement there is.

Answer 6 · 2012-12-16T14:38:17.000Z

http://chat.stackoverflow.com/transcript/11?m=6712152#6712152

Answer 7 · 2013-02-10T06:19:11.000Z

Added superset/subset functionality: f14ff53

Answer 8 · 2013-02-11T08:44:24.000Z

Well done ..... let me do some testing and see how it performs .....

Answer 9 · 2013-02-11T15:24:47.000Z

I highly recommend HashSet for this. SortedSet is abysmal when compared to HashSet. SortedSet is more for maintaining order than anything else.

Answer 10 · 2013-06-19T21:37:23.000Z

For most intents and purposes, this is now closed and implemented. If the need arises for some set operation that is currently missing then it deserves its own ticket.