Rolf: I showed where that came from in the post of a few days ago where I posted the entire program. I have a hash, %threads. The key is a string $thread, and the value is an array of numbers. This is how I printed the hash after it was constructed: foreach $thread (keys %threads) { print "$thread: @{$threads{$thread}}\n";} And that worked properly, exactly as expected. The code I posted here was an attempt to transfer the end arrays from members of the hash to members of an array. I initially tried to transfer each array as a whole. That gave me the problems I described in the previous post. The answers I got then didn't help, so I thought I'd try to do less cleverly, and transfer the elements of the array rather than the whole array. That's where the index $i comes from.