Golang 统计字母，数字，空格等字符个数

代码案例：

package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
)

type CharCount struct {
	chCount    int //英文个数
	NumCount   int //数字个数
	SpaceCount int //空格个数
	OtherCount int //其它字符个数
}

func main() {
	fileName := "./test1.txt"
	file, err := os.Open(fileName)
	if err != nil {
		fmt.Println("open file err=%v\n", err)
	}
	defer file.Close()
	var count CharCount
	//创建一个Reader
	reader := bufio.NewReader(file)
	//开始循环读取 fileName 文件内容
	for {
		str, err := reader.ReadString('\n')
		for _, v := range str {
			switch {
			case v >= 'a' && v <= 'z':
				fallthrough //穿透
			case v >= 'A' && v <= 'Z':
				count.chCount++
			case v == ' ' || v == '\t':
				count.SpaceCount++
			case v >= 0 || v <= 9:
				count.NumCount++
			default:
				count.OtherCount++
			}
		}
		if err == io.EOF { //读取到文件末尾就结束
			break
		}
	}
	fmt.Printf("英文的个数为=%v，数字的个数为=%v，空格的个数为=%v，其它的个数为=%v\n",
		count.chCount, count.NumCount, count.SpaceCount, count.OtherCount)
}

func CopyFile(dstFileName string, srcFileName string) (written int64, err error) {
	//打开srcFileName
	srcFile, err := os.Open(srcFileName)
	if err != nil {
		fmt.Println("open file err=%v\n", err)
	}
	//通过srcFile，获取到Reader
	reader := bufio.NewReader(srcFile)
	defer srcFile.Close()
	//打开dstFileName
	dstFile, err := os.OpenFile(dstFileName, os.O_WRONLY|os.O_CREATE, 0666)
	if err != nil {
		fmt.Println("open file err=%v\n", err)
	}
	//通过distFile，获取到Writer
	writer := bufio.NewWriter(dstFile)
	defer dstFile.Close()
	return io.Copy(writer, reader)
}