Great ideas from tjinc (with the invisible character, unicode 200b)
and Mayinbongwe (to make it more readable)!
Maybongwe's formula needs two adaptations within RxReplace to work:
* escaping the | or enclosing it in square brackets
* adding a negative lookbehind, otherwise non-leading zeros are also replaced by spaces
This is the new formula, with -- in the same stride -- a user-friendlier separator:
$RxReplace($Pad($Sum(<Play Count>,<Composer>),4)" → "$Split(<Composer>,;,1),"(?<![1-9])0(?! → )"," ")
@Artesoll, if you use the virtual tag in the Thumbnail explorer, use
Sort by -> Name and
Group by -> No grouping.
Sort by -> Count will sort by the album count computed for each entry, so in that case the list order won't match what you expect.
But I don't see why the order would be disturbed with
Sort by -> Name and
Group by -> No grouping.
In the Thumbnail explorer, sorting is done in ascending order only, thus lowest counts at the top, highest counts at the bottom.
However, descending order is possible in the column browser (highest counts at the top).
To illustrate the difference, you can find below a screenshot combining both options,
with 'PlayCountByComposer'.
Left pane = left main panel, thumbnail browser
Middle pane = main panel, column browser - vertical (stacked)
Right pane = main panel, files - Albums view
(Clicking on a column browser header, 'PlayCountByComposer' in this case, switches the sorting order: ascending/descending.)

EDIT: typo