📜  高朗 |如何在字符串找到符文的索引?

📅  最后修改于: 2021-10-25 02:51:42             🧑  作者: Mango

在 Go 语言中,字符串不同于Java、C++、 Python等其他语言。它是一系列可变宽度字符,其中每个字符都由一个或多个使用 UTF-8 编码的字节表示。
在 Go字符串,您还可以使用IndexRune()函数找到给定字符串指定符文的第一个索引。此函数返回 Unicode 代码点的第一个实例的索引,即指定的符文,如果指定的符文不存在于给定的字符串,则返回 -1。如果符文是utf8.RuneError ,则它返回任何无效 UTF-8 字节序列的第一个实例。它定义在字符串包下,因此您必须在程序中导入字符串包才能访问 IndexRune函数。

句法:

func IndexRune(str string, r rune) int

示例 1:

// Go program to illustrate how to find
// the index value of the given rune
package main
  
import (
    "fmt"
    "strings"
)
  
func main() {
  
    // Creating and Finding the first index 
    // of the rune in the given string
    // Using IndexRunefunction
    res1 := strings.IndexRune("****Welcome to GeeksforGeeks****", 60)
  
    res2 := strings.IndexRune("Learning how to trim"+
                           " a slice of bytes", 'r')
  
    res3 := strings.IndexRune("GeeksforGeeks", 'G')
  
    // Display the results
    fmt.Println("Index Value 1: ", res1)
    fmt.Println("Index Value 2: ", res2)
    fmt.Println("Index Value 3: ", res3)
  
}

输出:

Index Value 1:  -1
Index Value 2:  3
Index Value 3:  0

示例 2:

// Go program to illustrate how to find
// the index value of the given rune
package main
  
import (
    "fmt"
    "strings"
)
  
func main() {
  
    // Creating and initializing a string
    // Using shorthand declaration
    string_1 := "Welcome to GeeksforGeeks"
    string_2 := "AppleAppleAppleAppleAppleApple"
    string_3 := "%G%E%E%K%S"
  
    // Creating and initializing rune
    var r1, r2, r3 rune
    r1 = 'R'
    r2 = 'l'
    r3 = 42
  
    // Finding the first index
    // of the given rune
    // Using IndexRune function
    res1 := strings.IndexRune(string_1, r1)
    res2 := strings.IndexRune(string_2, r2)
    res3 := strings.IndexRune(string_3, r3)
  
    // Display the results
    fmt.Printf("String 1: %s , Rune 1:%q , Index Value: %d",
                                         string_1, r1, res1)
      
    fmt.Printf("\nString 2: %s , Rune 2:%q , Index Value: %d",
                                           string_2, r2, res2)
      
    fmt.Printf("\nString 3: %s , Rune 3:%q , Index Value: %d", 
                                           string_3, r3, res3)
  
}

输出:

String 1: Welcome to GeeksforGeeks , Rune 1:'R' , Index Value: -1
String 2: AppleAppleAppleAppleAppleApple , Rune 2:'l' , Index Value: 3
String 3: %G%E%E%K%S , Rune 3:'*' , Index Value: -1