Benchmark: timing 1000000 iterations of split, substr...
     split:  8 wallclock secs ( 6.93 usr +  0.00 sys =  6.93 CPU) @ 144279.32/s(n=1000000)
    substr:  1 wallclock secs ( 1.54 usr +  0.00 sys =  1.54 CPU) @ 648088.14/s(n=1000000)