// concatstrings implements a Go string concatenation x+y+z+...// The operands are passed in the slice a.// If buf != nil, the compiler has determined that the result does not// escape the calling function, so the string data can be stored in buf// if small enough.funcconcatstring...
funcConcat4(args...interface{})string{a:="default-a"b:=5for_,arg:=range args{switcht:=arg.(type){casestring:a=tcaseint:b=tdefault:panic("Unknown argument")}}returnfmt.Sprintf("%s%d",a,b)} 相当泛用的方法,但是对于不同的类型就不可行了。
)var strLen int = 1000func BenchmarkConcatString(b *testing.B) { var str string i := 0 b.ResetTimer() for n :=0; n< b.N; n++ { str += "X" i++ if i >= strLen { i = 0 str = "" } } }func BenchmarkConcatBuffer(b *testing.B) { ...
fori :=0; i < b.N; i++ { slice := []int{} slice =append(slice, []int{0,0,0,0,0}...) } } // 优化版本 funcBenchmarkAppendZeros2(b *testing.B){ fori :=0; i < b.N; i++ { slice := []int{} slice =append(slice,make([]int,5)...) } } 测试结果: goos: wi...
var ip = flag.Int("num", 1234, "help message for flagname")var real string flag.StringVar(&real, "s", "this is a test","help msg for dir")flag.Parse()fmt.Println(*ip)fmt.Println(real)} 编译 go build test.go ./test -num3333 -s aaaaaaa 输出 // 3333 //aaaaaaa 在Rust中，...
func concat(n int) string { var s strings.Builder for i := 0; i < n; i++ { s.WriteString(randomString(n)) } return s.String() } 接下来,重新运行程序: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 go run main.go 2021/05/31 20:22:12 profile: memory profiling enabled (ra...
packagestringutilimport("strings""testing")// Concat concatenates a slice of strings.funcConcat(strs[]string)string{returnstrings.Join(strs,"")}funcBenchmarkConcat(b*testing.B){strs:=[]string{"Hello","World","This","Is","Go"}fori:=0;i...
func join(s1, s2 string, max int) (string, error) { if s1 == "" { return "", errors.New("s1 is empty") } if s2 == "" { return "", errors.New("s2 is empty") } concat, err := concatenate(s1, s2) if err != nil { return "", err } if len(concat) > max { retu...
type User struct { ID string `gorm:"default:uuid_generate_v3()"` // db func FirstName string LastName string Age uint8 FullName string `gorm:"->;type:GENERATED ALWAYS AS (concat(firstname,' ',lastname));default:(-);"` } 1. 2. 3. 4. 5. 6. 7. Upsert冲突 gorm为不同数据库...
Concat()多个流拼接的方式创建出一个串行执行stream串行流对象 Stream中间处理 主要负责对Stream进行处理操作,并返回一个新的Stream对象,中间处理操作可以进行叠加。 API功能说明 Filter()按照条件过滤符合要求的元素, 返回新的stream流 Map()按照条件将已有元素转换为另一个对象类型,一对一逻辑,返回新类型的str...