Action Regex Help: copy features from title to artist with \\ separation

Support
1

I've gone a bit cross-eyed trying to work out this RegEx. Here is an example of what I'm hoping to do:

TITLE: That's Just How It Is (feat. Ty Dolla $ign, Leon Thomas & The-Dream)
ARTIST: A$AP Rocky

I would like the title to remain unchanged but I would like artist to change to:

ARTIST: A$AP Rocky\\Ty Dolla $ign\\Leon Thomas\\The-Dream

The closest I have come is this:

ACTION: Guess Values
SOURCE FORMAT: $regexp(%artist% - %title%,(.*) - (.*) \(feat. (.*)\),$1\\\\$3)
GUESSING PATTERN: %artist%

which gives:

ARTIST: A$AP Rocky\\Ty Dolla $ign, Leon Thomas & The-Dream

How can I split $3 into the individual items and apply the \\\\ between each?

For further use it should also account for the fact that sometimes there's only a single artist featured ex: (feat. Ty Dolla $ign). If there are exactly two featured artists it is often with an ampersand only and no commas ex: (feat. Ty Dolla $ign & The-Dream). Three or more artists is as the original example, comma separated until the final two which are ampersand separated.

Any help greatly appreciated!

edit tldr:
BEFORE
TITLE: That's Just How It Is (feat. Ty Dolla $ign, Leon Thomas & The-Dream)
ARTIST: A$AP Rocky

AFTER
TITLE: That's Just How It Is (feat. Ty Dolla $ign, Leon Thomas & The-Dream)
ARTIST: A$AP Rocky\\Ty Dolla $ign\\Leon Thomas\\The-Dream

2

The \\ indicate a multi-value field that you have to merge first to get access to all of the data in 1 string.
Use $meta_sep(artist, & ) or a suitable different separator from the & and then apply "Guess value".

3

I'm not sure I understand how that would work here. The data is all in one string already (the title), I want to take that and add it to the artist field, thus changing artist to a multi-value field in the process.

4

I misunderstood, sorry.
You could try:
%artist%\\$replace($regexp(%title%,'(.*) \(feat. (.*)\)',$2),', ',\\, & ,\\)
You would not need "Guess value" but "Format value" would work just as fine as you do not split the contents into different fields.

5

That is perfect! Thank you so much.