Schwartzian Transform

         @sorted_names = 
           map { $_->[0] }
           sort { $b->[1] <=> $a->[1] } 
           map { [ $_, -M $_ ] } 
           readdir D;

• This is more complicated and more work than the original code:

        sort { -M $b <=> -M $a } readdir D;

• Is it really faster?

• To find out, we run both versions on the same data

  • We measure the time taken by each one

• This is called a benchmark

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Copyright © 2003 M. J. Dominus