strings.Contains vs regexp.MatchString

bench_substrings_match_test.go

package bench

import (
	"regexp"
	"strings"
	"testing"
)

var (
	inputTexts = []string{
		"カワ",
		"カワウソ",
		"otter",
		"ot",
	}

	names = []string{"コツメカワウソ",
		"オオカワウソ",
		"ユーラシアカワウソ",
		"ビロードカワウソ",
		"ツメナシカワウソ",
		"かわうそ",
		"otter",
		"sea otter",
		"liver otter",
		"ラッコ",
	}
)

func BenchmarkStringsContains(b *testing.B) {
	for n := 0; n < b.N; n++ {
		for _, inputText := range inputTexts {
			for _, name := range names {
				strings.Contains(name, inputText)
				// fmt.Printf("%s, %s: %v\n", name, inputText, strings.Contains(name, inputText))
			}
		}
	}
}

func BenchmarkRegexMatchString(b *testing.B) {
	for n := 0; n < b.N; n++ {
		for _, inputText := range inputTexts {
			for _, name := range names {
				regexp.MatchString(inputText, name)
				// fmt.Printf("%s, %s: %v\n", name, inputText, res)
			}
		}
	}
}

Result

% go test -bench . -benchmem
BenchmarkStringsContains-8    	 2360593	       479.9 ns/op	       0 B/op	       0 allocs/op
BenchmarkRegexMatchString-8   	   39990	     28784 ns/op	   46446 B/op	     620 allocs/op