UI workflow for set membership filter

[wesm]

This is the multiset "is-member-of" filter provided by isin in pandas or %in% in R.

• Should support locating values by searching, with the option of "select all matching search term"
• Should perhaps display frequency of each value, with the ability to see the most frequently occurring values at the top (as opposed to lexically ordering values)

[wesm]

As some food for thought about what features we might want, consider the "Filter by values" dropdown for the Table feature in Google sheets:

When I type in the search box, it only shows values matching the search string (case insensitive):

As a refinement over this, given that we can compute the frequency table for columns, it would be nice to have the option to see the values not just alphabetically but also ordered by frequency.

[wesm]

Rill Data is another tool that has as similar kind of set-membership selector, with an exclusion toggle which is nice: