slice string filtering

utils_benchmark_test.go

package utils

import (
	"testing"
)

func BenchmarkFilterSlice(b *testing.B) {
	p := []string{"pika", "pi", "chu", "piika"}
	p2 := []string{"pika", "pi", "chu"}

	for i := 0; i < b.N; i++ {
		tb := []string{}
		for _, bi := range p {
			for _, b := range p2 {
				if bi == b {
					tb = append(tb, bi)
					break
				}
			}
		}
		p = tb
	}
}

func BenchmarkFilterSlice2(b *testing.B) {
	p := []string{"pika", "pi", "chu", "piika"}
	p2 := []string{"pika", "pi", "chu"}

	for i := 0; i < b.N; i++ {
		tb := make([]string, len(p))
		var cnt int
		for _, bi := range p {
			for _, b := range p2 {
				if bi == b {
					tb[cnt] = bi
					cnt++
					break
				}
			}
		}
		p = tb[:cnt]
	}
}

// BenchmarkFilterSlice-8    	 5000000	       244 ns/op	     112 B/op	       3 allocs/op
// BenchmarkFilterSlice2-8   	20000000	        94.0 ns/op	      48 B/op	       1 allocs/op