[icen]

A related operator is group (=), which creates a map between the unique elements of a list to their locations.

     x: 10 ? `a`b`c
     x
    `a`c`c`c`c`a`b`a`a`c
     =x
    a|0 5 7 8  
    b|,6       
    c|1 2 3 4 9