Check If the Rune is an Uppercase Letter or not in Golang

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 check the given rune is an upper case letter or not with the help of IsUpper() function. This function returns true if the given rune is an upper case letter, or return false if the given rune is not an upper case letter. This function is defined under Unicode package, so for accessing this method you need to import the Unicode package in your program.

Syntax:

func IsUpper(r rune) bool

The return type of this function is boolean. Let us discuss this concept with the help of given examples:

Example 1:

// Go program to illustrate how to check
// the given rune is an uppercase letter
// or not
package main

import (
    "fmt"
    "unicode"
)

// Main function
func main() {

    // Creating rune
    rune_1 := 'g'
    rune_2 := 'e'
    rune_3 := 'E'
    rune_4 := 'k'
    rune_5 := 'S'

    // Checking the given rune is
    // an upper case letter or not
    // Using IsUpper() function
    res_1 := unicode.IsUpper(rune_1)
    res_2 := unicode.IsUpper(rune_2)
    res_3 := unicode.IsUpper(rune_3)
    res_4 := unicode.IsUpper(rune_4)
    res_5 := unicode.IsUpper(rune_5)

    // Displaying results
    fmt.Println(res_1)
    fmt.Println(res_2)
    fmt.Println(res_3)
    fmt.Println(res_4)
    fmt.Println(res_5)

}

Output:

false
false
true
false
true

Example 2:

// Go program to illustrate how to check
// the given rune is an Uppercase letter
// or not
package main

import (
    "fmt"
    "unicode"
)

// Main function
func main() {

    // Creating a slice of rune
    val := []rune{'g', 'E', 'e', 'K', 's'}

    // Checking each element of the given
    // slice of the rune is an uppercase
    // letter or not
    // Using IsUpper() function
    for i := 0; i < len(val); i++ {

        if unicode.IsUpper(val[i]) == true {

            fmt.Printf("\n%c is an uppercase letter", val[i])

        } else {

            fmt.Printf("\n%c is not an uppercase letter", val[i])
        }
    }
}

Output:

g is not an uppercase letter
E is an uppercase letter
e is not an uppercase letter
K is an uppercase letter
s is not an uppercase letter