OK, one last test and I promise I'm done. I tried the same as above but with 1000 iterations: 
Method 5 is while (my $line = <TOP>) with open(TOP, "top -b -n 1|") and creating the hash keys as we go.
Method 6 is while (my $line = <TOP>) with open(TOP, "top -b -n 1|") and precreating the hash keys.
Method 5 mean:  0.557365287780762 stddev:  0.00308031218339066!
Method 6 mean:  0.557536187648773 stddev:  0.00521559192260659!
T-stat for mean 5 and mean 6 is 0.892202830875346
So the mean is slightly significantly lower for creating on-the-fly, and the variance is significantly lower for that approach. Interesting.
I like computer programming because it's like Legos for the mind.

In reply to Re^2: How best to tell when my hash is "full" (all values defined)? by OfficeLinebacker
in thread How best to tell when my hash is "full" (all values defined)? by OfficeLinebacker

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