How to deal with question answered only in comments, when wanting to help clean up "unanswered questions"? [duplicate]

Question

This is a common trend that I saw while trying to find questions suitable for me to answer. The filter and sorting problem of the questions was more or less solved for me by my previous question. But then again arises a new problem(minor as it seems to me). That is most of the questions with no answers has been solved in the comments and no one bothered to write an answer. I get it that it was pragmatic in those circumstances nevertheless it makes the searching for suitable questions tiresome. So I would like to hear the thoughts that how should I go about that.

Is there any way that they don't feature in the unanswered tab? Can adding a tag or filter be an answer?

Some examples may be:

1. Gateaux and Frechet derivatives and boundedness
2. How to understand the similarities and differences between subset and subspace? Examples?

Edit: Like every one of you suggested a major chunk of the question is answered here and by the linked meta post, courtesy of Asaf Karagila, hardmath, Eevee Trainer and Andrew T. Still as amWhy suggested a minor portion of the problem remains unsolved, namely cleaning up the unanswered tab. Even if someone is just answering it with help from the comments still it remains in the unanswered tab(which seems unlikely but is happening somehow) till it's upvoted.

What I am asking is a way to separate these questions from the questions that have not received help or are not fully solved.

Ce sera sera!

Answer 1

How to deal with question answered only in comments, when wanting to help clean up “unanswered questions”?

Typically, what I've heard and occasionally done would be thus:

• Write the essential details from the comments into an answer post.
• Do give credit where credit is due, naming those who provided the relevant details in your post.
• Add any useful details and such you yourself might perhaps know, outside sources, etc.
• Mark the answer as a community wiki answer, perhaps adding a small tidbit at the top of the post to clarify why you're making this post. (It's unanswered but has answers in the comments.)
• Post it.

Of course, this does bear some further notes with respect to when this should be done:

• Try to do this only to answers you yourself know about, or at least have the skill to verify. This is in case the question/comments are a bit above your head; maybe the answer in the comments is wrong, or incomplete. Just make sure you can verify the validity of what's being said.

• If you can offer an extensive amount of extra details - perhaps an alternate approach or such, or fleshing out nudges towards a complete answer - it might be better to make a separate answer altogether, one altogether your own. You could mention/summarize the solution in the comments in the leading bit of your post before going into your own solution. (Of course, you could also offer up your own solution in the community wiki bit, that's entirely up to you. I just think that, if the majority of the post is genuinely content you made, it's better for you to make it a post by you as opposed to by the community.)

• If the solution was made by or mostly by one individual but done in the comments, perhaps trying @ing them and seeing if they're willing to present their own write-up as an answer post instead. This would probably be best so they can get the rep their answer deserves, but depending on the question and users involved, it's all too possible this might not be viable. Perhaps the user(s) went inactive, or something of the sort, or perhaps they're unwilling, in which case the community-wiki answer approach is probably best.