[swift-evolution] Additional methods for removing elements from a collection in Swift

[Xiaodi Wu]

What is the use case?
On Mon, Sep 25, 2017 at 23:27 Félix Cloutier <felixcloutier at icloud.com>
wrote:

> Actually, IMO, it's an oversight that there's no remove(where:), or
> another in-place equivalent to `filter`. I'm in favor of it.
>
> Félix
>
>
> Le 25 sept. 2017 à 15:17, Xiaodi Wu <xiaodi.wu at gmail.com> a écrit :
>
> On Mon, Sep 25, 2017 at 4:55 PM, Xiaodi Wu <xiaodi.wu at gmail.com> wrote:
>
>> Brent has a great proposal in the pipeline regularizing the names of some
>> of these functions and filling in some of the more glaring gaps.
>>
>> With regard to the specific items proposed here, Felix shows that
>> ‘filter’ provides an idiomatic one-line way of doing some of what is
>> proposed; currently remove(index(of:)) and operating on sliced would
>> accomplish the rest. Therefore, I do not think these proposed additions
>> meet the very high bar for expansion of the standard library API.
>
>
> I should add, however, it is wonderful (IMO) that more people are thinking
> about these APIs; welcome and thank you for restarting this very important
> conversation. It would be nice to get some more eyeballs on the previously
> discussed set of rationalizations to the Collection APIs so that we can
> make their use a little more ergonomic--with any luck, some better names
> for existing extension methods and filling in a very few gaps judiciously
> would allow us to make the existing facilities sufficiently more
> discoverable that it will be easier to accomplish what you seek without
> adding more extensions.
>
>
> On Mon, Sep 25, 2017 at 11:14 Félix Cloutier via swift-evolution <
>> swift-evolution at swift.org> wrote:
>>
>>> Another alternative is to use `array = array.filter { $0 != someElement
>>> }`.
>>>
>>> I thought that there would be a `remove(where:)` method, but there isn't.
>>>
>>> Félix
>>>
>>> Le 25 sept. 2017 à 02:12, Alwyn Concessao via swift-evolution <
>>> swift-evolution at swift.org> a écrit :
>>>
>>> Hello,
>>>
>>> After going through the Swift standard library functions provided for
>>> removing elements from a collection, one common pattern can be observed in
>>> all those functions and that is the functions provide to remove elements
>>> from the collection by passing the position or index of the element or
>>> passing a range of indices or positions to remove the elements.The standard
>>> library does not provide options to remove an element from a collection by
>>> passing the actual element  to be removed directly to the remove
>>> method.I've encountered this situation many times when programming in Swift
>>> wherein I want an element or a set of elements to be removed directly
>>> without always accessing it's index in the collection but I have always
>>> ended up having to first access the index of the element or elements which
>>> I want to remove and then pass that index to the remove method.
>>>
>>> The idea is to have an extension of the RangeReplaceableCollection
>>> protocol to include a method to remove elements from a collection by
>>> passing directly the element to be removed to the remove method and also
>>> include methods to remove multiple elements from the collection by passing
>>> in a sequence of the elements to be removed to the remove method and to
>>> remove an element in a particular subrange of the collection.
>>>
>>> The prototype of the methods will be as follows -
>>>
>>> extension RangeReplaceableCollection where Element:Equatable{
>>>
>>> mutating func removeElement(_ elementToBeRemoved:Element){
>>>
>>> //check if elementToBeRemoved exists ;if yes, remove all occurrences of
>>> elementsToBeRemoved from the collection.
>>>
>>> }
>>>
>>> mutating func removeElementInSubrange(_ elementToBeRemoved:Element,in
>>> range:Range<Index>){
>>>
>>> //check if elementoBeRemoved exists; if yes, check if the index of
>>> elementToBeRemoved is part of the subrange, if yes then remove else don't
>>> remove.
>>>
>>> }
>>>
>>> mutating func removeContentsOf<C:Collection>(_ elementsToBeRemoved:C){
>>>
>>> //check if each element in the elementsToBeRemoved sequence exists in
>>> the collection, if the element exists, remove it.
>>>
>>> }
>>>
>>> I've implemented the above in the pull request
>>> https://github.com/apple/swift/pull/12058
>>>
>>> Any thoughts/suggestions on this are appreciated.
>>>
>>> Thanks!
>>>
>>> Alwyn
>>>
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> swift-evolution mailing list
>>> swift-evolution at swift.org
>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>>
>>>
>>> _______________________________________________
>>> swift-evolution mailing list
>>> swift-evolution at swift.org
>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>>
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-evolution/attachments/20170926/44ccc9aa/attachment.html>