Golang切片连接成字符串的实现示例

func Join(elems []string, sep string) string

package main

import (
	"fmt"
	"strings"
)

func main() {
	s := []string{"foo", "bar", "baz"}
	fmt.Println(strings.Join(s, ", "))
}

// JoinE concatenates all elements of Array, Slice or String to a single string with a separator
// and returns an error if an error occurred.
// E.g. input []int{1, 2, 3} and separator ",", output is a string "1,2,3".
// It panics if a's Kind is not Array, Slice, or String.
func JoinE(a any, sep string) (string, error) {
	v := reflect.ValueOf(a)
	if v.Kind() == reflect.String {
		return JoinE(strings.Split(a.(string), ""), sep)
	}
	var s string
	for i := 0; i < v.Len(); i++ {
		if len(s) > 0 {
			s += sep
		}
		str, err := conv.ToStringE(v.Index(i).Interface())
		if err != nil {
			return "", err
		}
		s += str
	}
	return s, nil
}

// ToStringE casts any type to a string type.
func ToStringE(i any) (string, error) {
	i = indirectToStringerOrError(i)

	switch s := i.(type) {
	case string:
		return s, nil
	case bool:
		return strconv.FormatBool(s), nil
	case int:
		return strconv.Itoa(s), nil
	case int64:
		return strconv.FormatInt(s, 10), nil
	case int32:
		return strconv.Itoa(int(s)), nil
	case int16:
		return strconv.FormatInt(int64(s), 10), nil
	case int8:
		return strconv.FormatInt(int64(s), 10), nil
	case uint:
		return strconv.FormatUint(uint64(s), 10), nil
	case uint64:
		return strconv.FormatUint(uint64(s), 10), nil
	case uint32:
		return strconv.FormatUint(uint64(s), 10), nil
	case uint16:
		return strconv.FormatUint(uint64(s), 10), nil
	case uint8:
		return strconv.FormatUint(uint64(s), 10), nil
	case float64:
		return strconv.FormatFloat(s, 'f', -1, 64), nil
	case float32:
		return strconv.FormatFloat(float64(s), 'f', -1, 32), nil
	case json.Number:
		return s.String(), nil
	case []byte:
		return string(s), nil
	case template.HTML:
		return string(s), nil
	case template.HTMLAttr:
		return string(s), nil
	case template.URL:
		return string(s), nil
	case template.JS:
		return string(s), nil
	case template.JSStr:
		return string(s), nil
	case template.CSS:
		return string(s), nil
	case template.Srcset:
		return string(s), nil
	case nil:
		return "", nil
	case fmt.Stringer:
		return s.String(), nil
	case error:
		return s.Error(), nil
	default:
		return "", fmt.Errorf("unable to cast %#v of type %T to string", i, i)
	}
}

// Copied from html/template/content.go.
// indirectToStringerOrError returns the value, after dereferencing as many times
// as necessary to reach the base type (or nil) or an implementation of fmt.Stringer
// or error.
func indirectToStringerOrError(a any) any {
	if a == nil {
		return nil
	}
	v := reflect.ValueOf(a)
	for !v.Type().Implements(fmtStringerType) && !v.Type().Implements(errorType) && v.Kind() == reflect.Pointer && !v.IsNil() {
		v = v.Elem()
	}
	return v.Interface()
}

// Join concatenates all elements of Array, Slice or String to a single string with a separator.
func Join(a any, sep string) string {
	s, _ := JoinE(a, sep)
	return s
}

package main

import (
	"fmt"
	"strings"
)

func main() {
	s := []string{"foo", "bar", "baz"}
	fmt.Println(Join(s, ", "))
	
	i := []int{1, 2, 3}
	fmt.Println(Join(i, ", "))

	f := []float64{1.1, 2.2, 3.3}
	fmt.Println(Join(f, ", "))
	
	b := []bool{true, false, true}
	fmt.Println(Join(b, ", "))

	// 可以将字符串看成字符切片。
	str := "foo"
	fmt.Println(Join(str, ", "))
}

import (
	"github.com/dablelv/cyan/str"
)

str.Join([]string{"foo", "bar", "baz"}, ", ")
str.Join([]int{1, 2, 3}, ", ")
str.Join([]float64{1.1, 2.2, 3.3}, ", ")
str.Join([]bool{true, false, true}, ", ")
str.Join("foo", ", ")