List interface lacks simple remove(index) method

[sethladd]

Let's add a remove(index) method to List. Something like http://docs.oracle.com/javase/1.4.2/docs/api/java/util/List.html#remove(int)

[floitschG]

Removed Type-Defect label.
Added Type-Enhancement, Area-Library, Triaged labels.

[sethladd]

A proposal is to name the method removeAt(index) to be more clear this is "remove the object at this index" and not "find the object and then remove it

[sethladd]

cc @lrhn.
Added Library-Core label.

[lrhn]

Added Accepted label.

[jmesserly]

+1, had to create my own "utils" with a "removeAt" method yet again ...

[sethladd]

Added this to the Later milestone.

[jmesserly]

I hope Milestone-Later means Milestone-Soon though :). The collection APIs badly need a facelift

[jmesserly]

also there was a request for "removeItem", which I think means remove(T item), essentially removeAt(indexOf(item)) (ignoring the item not found check)

[lrhn]

removeItem is dangerous in a List. It can mean either removeFirst or removeAll. I'd rather have both of those.

[jmesserly]

@LRN: totally agree

[alan-knight]

Clarity is good, but so is brevity, so I dislike making all the names longer so we can remove all possible ambiguities. It might be sufficiently non-confusing if one of them was just called remove. e.g. if there's a remove() and a removeAll().

[munificent]

+1 for remove()/removeAll().

It might be nice if remove() was in Collection so that you can have code that can generically remove from a List/Map/Set. In that case, removeFirst() isn't meaningful: what's the "first" matching item in a set?

[jmesserly]

That also matches what we do with "query" and "queryAll" from the DOM

[DartBot]

This comment was originally written by @seaneagan

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I would say "removeAll" is the vast majority use case, and I could easily see someone assuming that "removeAll" takes a Collection of elements to remove from the receiver Collection. I think "removeFirst" is rare, and as jmesserly noted, easily written in terms of "indexOf", so I would leave it out, but if it's there, maybe call it "removeOne" in order to make it make sense for Sets as well.

[alan-knight]

Interesting? I think that removeFirst is common and removeAll rare. Or, more particularly, I think that collections without duplicates is the most common case, so the two are equivalent and removeFirst is faster. And writing it in terms of indexOf every time is horrible.

[DartBot]

This comment was originally written by @seaneagan

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I totally agree that Collections without duplicates are the most common,
but those really should be Sets or possibly OrderedSets, not Lists, in
which case "removeAll" can be optimized to behave the same as
"removeFirst"/"removeOne", so there is no need for both. In the case where
you do have duplicates, I think it's rare that you would want to remove *
only* the first instance, and not all. I do seem to be the outlier here
though :).

[lrhn]

I can see that removeAll will be confusing when compared with Set.removeAll.
For consistency with Set, it might be better if "remove" would remove all instances of the element from the list, and a "removeFirst" (or similar) function could be used to remove only one instance (written in terms of indexOf and removeAt).

[DartBot]

This comment was originally written by @seaneagan

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@LRN: sounds good to me.

A couple things to consider if including a List#removeFirst:

* should it take an optional "startIndex" parameter like "indexOf" does?

• do we then need a corresponding "removeLast" to match "last", "lastIndexOf", "addLast"?

[DartBot]

This comment was originally written by @seaneagan

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I just realized there is a different semantics for "removeFirst" proposed, see issue #604, so this one would might need to be "removeFirstOccurrence" or something.