golang 判断是否字母

package main

import (
    "fmt"
    "unicode"
)

func main() {
    if unicode.IsLetter('A') {
        fmt.Println("A is a letter.")
    } else {
        fmt.Println("A is not a letter.")
    }
}

A is a letter.

package main

import (
    "fmt"
    "unicode"
)

func main() {
    str := "HelloWorld"
    allLetter := true
    for _, c := range str {
        if !unicode.IsLetter(c) {
            allLetter = false
            break
        }
    }
    if allLetter {
        fmt.Println(str, "contains only letters.")
    } else {
        fmt.Println(str, "contains non-letters.")
    }
}

HelloWorld contains only letters.