Benchmark: timing 10000000 iterations of comp, exist, regex, regexo... comp: 53 wallclock secs (53.96 usr + 0.00 sys = 53.96 CPU) exist: 49 wallclock secs (49.23 usr + 0.00 sys = 49.23 CPU) regex: 78 wallclock secs (77.40 usr + 0.00 sys = 77.40 CPU) regexo: 78 wallclock secs (77.12 usr + 0.00 sys = 77.12 CPU)