[ruby-core:89269] [Ruby trunk Feature#15198] Array#intersect?

[ruby-core:89269] [Ruby trunk Feature#15198] Array#intersect?

[c4am95]

Issue #15198 has been reported by c4am95 (Travis Hunter).

----------------------------------------
Feature #15198: Array#intersect?
https://bugs.ruby-lang.org/issues/15198

* Author: c4am95 (Travis Hunter)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
I frequently find myself needing to determine if two arrays intersect but not actually caring about the intersection, so I write code like:
~~~ ruby
(a1 & a2).any?
~~~

It would be nice to have an **intersect?** convenience method on **Array** to perform this query.

[ruby#1972: Add Array#intersect?](https://github.com/ruby/ruby/pull/1972)



-- 
https://bugs.ruby-lang.org/

[ruby-core:89273] [Ruby trunk Feature#15198] Array#intersect?

[shyouhei]

Issue #15198 has been updated by shyouhei (Shyouhei Urabe).


- Interesting.  Can you share a bit more detail about your "if two arrays intersect but not actually caring about the intersection" use case?  For instance if you have open sourced such code, a URL for it helps us a lot.

- If you have zero interest to the intersection itself I think you can avoid creating the temporary array.

----------------------------------------
Feature #15198: Array#intersect?
https://bugs.ruby-lang.org/issues/15198#change-74297

* Author: c4am95 (Travis Hunter)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
I frequently find myself needing to determine if two arrays intersect but not actually caring about the intersection, so I write code like:
~~~ ruby
(a1 & a2).any?
~~~

It would be nice to have an **intersect?** convenience method on **Array** to perform this query.

[ruby#1972: Add Array#intersect?](https://github.com/ruby/ruby/pull/1972)



-- 
https://bugs.ruby-lang.org/

[ruby-core:89287] [Ruby trunk Feature#15198] Array#intersect?

[c4am95]

Issue #15198 has been updated by c4am95 (Travis Hunter).


The most recent example I encountered was authorizing a user in a Rails endpoint. Each user has a list of abilities, and each endpoint has a list of abilities that is authorized to perform the action. We just need to check if there is an intersection between the two lists.

I updated the PR to avoid creating the intermediate array.

----------------------------------------
Feature #15198: Array#intersect?
https://bugs.ruby-lang.org/issues/15198#change-74316

* Author: c4am95 (Travis Hunter)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
I frequently find myself needing to determine if two arrays intersect but not actually caring about the intersection, so I write code like:
~~~ ruby
(a1 & a2).any?
~~~

It would be nice to have an **intersect?** convenience method on **Array** to perform this query.

[ruby#1972: Add Array#intersect?](https://github.com/ruby/ruby/pull/1972)



-- 
https://bugs.ruby-lang.org/

[ruby-core:89297] [Ruby trunk Feature#15198] Array#intersect?

[shevegen]

Issue #15198 has been updated by shevegen (Robert A. Heiler).


Demonstrated use cases helps the core team & matz assess on the usefulness of a proposed
change, which can help in accepting issue requests ultimately in the long run (if the
use case is considered sufficiently useful). :)

----------------------------------------
Feature #15198: Array#intersect?
https://bugs.ruby-lang.org/issues/15198#change-74331

* Author: c4am95 (Travis Hunter)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
I frequently find myself needing to determine if two arrays intersect but not actually caring about the intersection, so I write code like:
~~~ ruby
(a1 & a2).any?
~~~

It would be nice to have an **intersect?** convenience method on **Array** to perform this query.

[ruby#1972: Add Array#intersect?](https://github.com/ruby/ruby/pull/1972)



-- 
https://bugs.ruby-lang.org/

[ruby-core:89309] [Ruby trunk Feature#15198] Array#intersect?

[c4am95]

Issue #15198 has been updated by c4am95 (Travis Hunter).


I threw together a contrived example in a [gist](https://gist.github.com/travisofthenorth/eb2a68f5cd309dc7442ec4e1e55ae117) which is very similar to the use case I described. I have also run into numerous other situations where this functionality would have been useful.

I added some comments in the gist but I'll cross-post them here for reference:
> The current behavior creates an intermediate array for both intersection tests when the resulting array is clearly not needed. With the desired behavior, we could avoid creating the intermediate array and produce a faster best case runtime.

----------------------------------------
Feature #15198: Array#intersect?
https://bugs.ruby-lang.org/issues/15198#change-74338

* Author: c4am95 (Travis Hunter)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
I frequently find myself needing to determine if two arrays intersect but not actually caring about the intersection, so I write code like:
~~~ ruby
(a1 & a2).any?
~~~

It would be nice to have an **intersect?** convenience method on **Array** to perform this query.

[ruby#1972: Add Array#intersect?](https://github.com/ruby/ruby/pull/1972)



-- 
https://bugs.ruby-lang.org/

[ruby-core:89321] [Ruby trunk Feature#15198] Array#intersect?

[c4am95]

Issue #15198 has been updated by c4am95 (Travis Hunter).


It also seems like it comes up fairly commonly on stackoverflow/blogs:
https://stackoverflow.com/questions/2603895/how-can-i-check-if-a-ruby-array-includes-one-of-several-values
https://www.ruby-forum.com/t/find-if-an-array-has-any-element-present-in-another-array/166877
https://irb.rocks/comparison-arrays-ruby/
https://tosbourn.com/set-intersection-in-ruby/

----------------------------------------
Feature #15198: Array#intersect?
https://bugs.ruby-lang.org/issues/15198#change-74350

* Author: c4am95 (Travis Hunter)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
I frequently find myself needing to determine if two arrays intersect but not actually caring about the intersection, so I write code like:
~~~ ruby
(a1 & a2).any?
~~~

It would be nice to have an **intersect?** convenience method on **Array** to perform this query.

[ruby#1972: Add Array#intersect?](https://github.com/ruby/ruby/pull/1972)



-- 
https://bugs.ruby-lang.org/

[ruby-core:94776] [Ruby master Feature#15198] Array#intersect?

[daniel]

Issue #15198 has been updated by Dan0042 (Daniel DeLorme).


It might make sense to use `ary1.to_set.intersect?(ary2)`. That way it makes explicit the fact that ary1 must be converted to a set. But `Set#intersect?` would have to support any Enumerable.

----------------------------------------
Feature #15198: Array#intersect?
https://bugs.ruby-lang.org/issues/15198#change-81394

* Author: c4am95 (Travis Hunter)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
I frequently find myself needing to determine if two arrays intersect but not actually caring about the intersection, so I write code like:
~~~ ruby
(a1 & a2).any?
~~~

It would be nice to have an **intersect?** convenience method on **Array** to perform this query.

[ruby#1972: Add Array#intersect?](https://github.com/ruby/ruby/pull/1972)



-- 
https://bugs.ruby-lang.org/

[ruby-core:95508] [Ruby master Feature#15198] Array#intersect?

[c4am95]

Issue #15198 has been updated by c4am95 (Travis Hunter).


I tried setting that up here: https://github.com/ruby/ruby/pull/2598

I ignored infinite ranges for now

----------------------------------------
Feature #15198: Array#intersect?
https://bugs.ruby-lang.org/issues/15198#change-82284

* Author: c4am95 (Travis Hunter)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
I frequently find myself needing to determine if two arrays intersect but not actually caring about the intersection, so I write code like:
~~~ ruby
(a1 & a2).any?
~~~

It would be nice to have an **intersect?** convenience method on **Array** to perform this query.

[ruby#1972: Add Array#intersect?](https://github.com/ruby/ruby/pull/1972)



-- 
https://bugs.ruby-lang.org/