How to Map a Rune to the Specified Case in Golang?

Last Updated : 27 Sep, 2019

Rune is a superset of ASCII or it is an alias of int32. It holds all the characters available in the world’s writing system, including accents and other diacritical marks, control codes like tab and carriage return, and assigns each one a standard number. This standard number is known as a Unicode code point or rune in the Go language.
You are allowed to map a rune to the specified case with the help of To() function. This function changes the case of the given rune into lower case, or upper case, or title case according to your requirement. If the given rune is already present in the specified case, then this function does nothing. This function is defined under Unicode package, so for accessing this method you need to import the Unicode package in your program.

Syntax:

func To(_case int, r rune) rune

Example 1:

// Go program to illustrate how to 
// map a rune to the specified case 
package main 
  
import ( 
    "fmt"
    "unicode"
) 
  
// Main function 
func main() { 
  
    // Creating rune 
    rune_1 := 'g'
    rune_2 := 'e'
  
    // Mapping the given rune  
    // into the specified case 
    // Using To() function 
    fmt.Printf("Result 1: %c ", unicode.To(unicode.UpperCase, rune_1)) 
    fmt.Printf("\nResult 2: %c ", unicode.To(unicode.TitleCase, rune_2)) 
      
  
} 

Output:

Result 1: G 
Result 2: E

Example 2:

// Go program to illustrate how to 
// map a rune to the specified case 
package main 
  
import ( 
    "fmt"
    "unicode"
) 
  
// Main function 
func main() { 
  
    // Creating rune 
    rune_1 := 'E'
    rune_2 := 'K'
  
  
    // Mapping the given rune  
    // into the specified case 
    // Using To() function 
    fmt.Printf("\nResult 1: %c ", unicode.To(unicode.LowerCase, rune_1)) 
    fmt.Printf("\nResult 2: %c ", unicode.To(unicode.TitleCase, rune_2)) 
    fmt.Printf("\nResult 3: %c ", unicode.To(unicode.UpperCase, 's')) 
  
} 