Bug #12373
Updated by ksss (Yuki Kurihara) almost 8 years ago
I think that **str1.start_with?(str2)** is faster than **str1[0] == str2**. Because **str1.start_with?(str2)** just call **String#start_with?**, But **str1[0] == str2** make string object, call **String#[]**, make new String object **String#[]** and call **String#==**. (The patch is csv-shift.patch) Benchmark results. csv-benchmark.rb make temp CSV file and call **CSV#each** method(inner call **CSV#shift**) ~~~ $ ruby csv-benchmark.rb Warming up -------------------------------------- old_csv_shift 1.000 i/100ms new_csv_shift 1.000 i/100ms Calculating ------------------------------------- old_csv_shift 0.444 (± 0.0%) i/s - 3.000 in 6.759200s new_csv_shift 0.479 (± 0.0%) i/s - 3.000 in 6.264069s Comparison: new_csv_shift: 0.5 i/s old_csv_shift: 0.4 i/s - 1.08x slower ~~~ string-start_with.rb is a micro benchmark for **str1[0] == str2** and **str1.start_with?(str2)** ~~~ $ ruby string-start_with.rb Warming up -------------------------------------- a[0] == b 90.881k i/100ms a.start_with?(b) 115.557k i/100ms Calculating ------------------------------------- a[0] == b 1.836M (± 3.8%) i/s - 9.179M in 5.006568s a.start_with?(b) 3.183M (± 4.2%) i/s - 15.947M in 5.018654s Comparison: a.start_with?(b): 3183386.0 i/s a[0] == b: 1836263.5 i/s - 1.73x slower ~~~ Of course $ make test-all TESTS="test/csv/*" passed