test expression for collapse columns

Original author: galbith...@galbithink.org (December 15, 2010 06:06:12)

What steps will reproduce the problem?

1. Wide, sparse tables are awkward to explore because most columns are empty (or contain just one item). You have to keep scrolling right and left to see informative items. See, e.g.
   https://spreadsheets.google.com/pub?key=0AnZb5H7tDMvTdEx2eExqc0NRaURjT2djSDdLanZOWmc&hl=en&gid=0
2. How about expanding the "collapse column" options to include an option for a GREL test expression evaluated across all the column items in the selected rows? If the expression evaluates to true, the column is collapsed. If you didn't want to add this to the right/left collapse options for the individual columns, just having it in the all dropdown menu would be very handy. With the latter setup, the test expression would be applied to all the columns of the visible rows.

Original issue: http://code.google.com/p/google-refine/issues/detail?id=287

The issue names no files or tests; begin by locating the existing collapse-column options and the GREL evaluation entry points. Clarify whether the expression applies to selected or visible rows, then define tests showing when a column is collapsed or retained.