如何在Golang中找到指定字符串的索引值？

在Go语言中，字符串不同于其他语言，如Java, c++， Python等。它是一个变宽字符序列，其中每个字符都使用UTF-8编码由一个或多个字节表示。

在Go字符串中, 可以使用以下函数从原始字符串中找到指定字符串的第一个索引值。这些函数是在字符串包下定义的, 因此, 你必须在程序中导入字符串包才能访问这些功能：

1.索引：此函数用于从原始字符串中查找给定字符串的第一个实例的索引值。如果给定的字符串在原始字符串中不可用, 则此方法将返回-1。

语法如下：

func Index(str, sbstr string) int

这里, str是原始字符串, 并且str是一个我们要查找索引值的字符串。让我们借助示例来讨论这个概念：

例子：

//Go program to illustrate how to find
//the index value of the given string
package main
  
import (
     "fmt"
     "strings"
)
  
//Main function
func main() {
  
     //Creating and initializing the strings
     str1 := "Welcome to the online portal of srcmini"
     str2 := "My dog name is Dollar"
     str3 := "I like to play Ludo"
  
     //Displaying strings
     fmt.Println( "String 1: " , str1)
     fmt.Println( "String 2: " , str2)
     fmt.Println( "String 3: " , str3)
  
     //Finding the index value of the given strings
     //Using Index() function
     res1 := strings.Index(str1, "Geeks" )
     res2 := strings.Index(str2, "do" )
     res3 := strings.Index(str3, "chess" )
     res4 := strings.Index( "srcmini, geeks" , "ks" )
  
     //Displaying the result
     fmt.Println( "\nIndex values:" )
     fmt.Println( "Result 1: " , res1)
     fmt.Println( "Result 2: " , res2)
     fmt.Println( "Result 3: " , res3)
     fmt.Println( "Result 4: " , res4)
  
}

输出如下：

String 1:  Welcome to the online portal of srcmini
String 2:  My dog name is Dollar
String 3:  I like to play Ludo

Index values:
Result 1:  32
Result 2:  3
Result 3:  -1
Result 4:  3

2. IndexAny：此方法从原始字符串中的chars返回任何Unicode代码点的第一个实例的索引。如果来自chars的Unicode代码点在原始字符串中不可用, 则此方法将返回-1。

语法如下：

func IndexAny(str, charstr string) int

这里, str是原始字符串, 并且查斯特是chars的Unicode代码点, 我们想要查找索引值。

例子：

//Go program to illustrate how to find
//the index value of the given string
package main
  
import (
     "fmt"
     "strings"
)
  
//Main function
func main() {
  
     //Creating and initializing the strings
     str1 := "Welcome to the online portal of srcmini"
     str2 := "My dog name is Dollar"
     str3 := "I like to play Ludo"
  
     //Displaying strings
     fmt.Println( "String 1: " , str1)
     fmt.Println( "String 2: " , str2)
     fmt.Println( "String 3: " , str3)
  
     //Finding the index value
     //of the given strings
     //Using  IndexAny() function
     res1 := strings.IndexAny(str1, "G" )
     res2 := strings.IndexAny(str2, "do" )
     res3 := strings.IndexAny(str3, "lqxa" )
     res4 := strings.IndexAny( "srcmini, geeks" , "uywq" )
  
     //Displaying the result
     fmt.Println( "\nIndex values:" )
     fmt.Println( "Result 1: " , res1)
     fmt.Println( "Result 2: " , res2)
     fmt.Println( "Result 3: " , res3)
     fmt.Println( "Result 4: " , res4)
  
}

输出如下：

String 1:  Welcome to the online portal of srcmini
String 2:  My dog name is Dollar
String 3:  I like to play Ludo

Index values:
Result 1:  32
Result 2:  3
Result 3:  2
Result 4:  -1

3. IndexByte：此函数返回原始字符串中给定字节的第一个实例的索引。如果给定的字节在原始字符串中不可用, 则此方法将返回-1。

语法如下：

func IndexByte(str string, b byte) int

这里, str是原始字符串, 并且b是一个字节, 我们要查找其索引值。让我们借助示例来讨论这个概念：

例子：

//Go program to illustrate how to find
//the index value of the given bytes
package main
  
import (
     "fmt"
     "strings"
)
  
//Main function
func main() {
  
     //Creating and initializing the strings
     str1 := "Welcome to the online portal of srcmini"
     str2 := "My dog name is Dollar"
     str3 := "I like to play Ludo"
  
     //Displaying strings
     fmt.Println( "String 1: " , str1)
     fmt.Println( "String 2: " , str2)
     fmt.Println( "String 3: " , str3)
  
     //Finding the index value of the given bytes
     //Using IndexByte() function
     res1 := strings.IndexByte(str1, 'c' )
     res2 := strings.IndexByte(str2, 'o' )
     res3 := strings.IndexByte(str3, 'q' )
     res4 := strings.IndexByte( "srcmini, geeks" , 'G' )
  
     //Displaying the result
     fmt.Println( "\nIndex values:" )
     fmt.Println( "Result 1: " , res1)
     fmt.Println( "Result 2: " , res2)
     fmt.Println( "Result 3: " , res3)
     fmt.Println( "Result 4: " , res4)
  
}

输出如下：

String 1:  Welcome to the online portal of srcmini
String 2:  My dog name is Dollar
String 3:  I like to play Ludo

Index values:
Result 1:  3
Result 2:  4
Result 3:  -1
Result 4:  0