Re^3: read hash table from a subroutine or retrieve previously stored hash table from a file

[Kenosis]

Then, somehow, entires from column 2 (the groups' column) became keys in your 'hash table.' You need to discover how this happened, since the groupByCol2 subroutine merely uses your 'hash table's' values as keys and associates them with references to anonymous arrays which contain name entires.