go Language: Get string length

go underlying implementation language string byte array, using UTF-8 encoding, it can not be changed after the initialization

Get string length

First, when all the characters in the string are single-byte characters, using the  len  function to get the length of the string

package main

import "fmt"

func main() {
    var str string
    str = "Hello world"
    fmt.Printf("The length of \"%s\" is %d. \n", str, len(str))
}

Enter the above program results: The length of "Hello world" is 11.

Second, when a string contains multi-byte characters when there are two ways to obtain the length of the string

1, use standard library  utf8  in  RuneCountInString  function to obtain the length of the string

package main

import (
	"fmt"
	"unicode/utf8"
)

func main() {
    str := "Hello, 世界"
    fmt.Println("bytes =", len(str))
    fmt.Println("runes =", utf8.RuneCountInString(str))
}

Enter the above program results:

bytes = 13
runes = 9

2, to convert the string to rune slices , then len obtaining length function

package main

import (
	"fmt"
)

func main() {
	str := "Hello, 世界"
	runes := []rune(str)
	fmt.Printf("The byte length of \"%s\" a is %d \n", str, len(str))
	fmt.Printf("The length of \"%s\" a is %d \n", str, len(runes))
}

The above program output:

The byte length of "Hello, 世界" a is 13
The length of "Hello, 世界" a is 9