Re^2: Stepping through a hash while modifiying its content

[Gorgarian]

That is a good suggestion too -- I could run the code in blocks, saving up the deletions, and doing a clean-up after each 1M iterations, then restarting the while loop. I will see how much longer it takes to run after restricting myself to deleting only deleting the most recent iteration reference, and if it is a problem, move to your idea as a Plan B.

Thanks for your help. Learning ... :)