Go-文件(2)

将一个文件内容写入到另一个文件

package main

import (
	"fmt"
	"io/ioutil"
)

func main() {
	file1Path := "C:/Users/pc/Desktop/1.txt"
	file2Path := "C:/Users/pc/Desktop/2.txt"
	data, err := ioutil.ReadFile(file1Path)
	if err != nil {
		fmt.Printf("err=%v", err)
		return
	}
	err = ioutil.WriteFile(file2Path, data, 0666)
	if err != nil {
		fmt.Printf("err=%v", err)
	}
}

判断文件是否存在

拷贝文件

将一张照片/电影/MP3拷贝到另一个目录下

package main

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

func CopyFile(dstFileName string, srcFileName string) (written int64, err error) {
	srcfile, err := os.Open(srcFileName)
	if err != nil {
		fmt.Printf("err=%v", err)
	}
	defer srcfile.Close()
	reader := bufio.NewReader(srcfile)
	dstfile, err := os.OpenFile(dstFileName, os.O_WRONLY|os.O_CREATE, 0666)
	if err != nil {
		fmt.Printf("err=%v", err)
		return
	}
	writer := bufio.NewWriter(dstfile)
	defer dstfile.Close()
	return io.Copy(writer, reader)
}

func main() {
	//将flower.jpg文件拷贝到abc.jpg

	srcfile := "C:/Users/pc/Desktop/1/1.png"
	dstfile := "C:/Users/pc/Desktop/2/2.png"
	_, err := CopyFile(dstfile, srcfile)
	if err == nil {
		fmt.Println("拷贝完成")
	} else {
		fmt.Printf("err=%v", err)
	}
}

统计英文、数字、空格和其他字符数量

package main

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

type CharCount struct {
	chCount    int
	NumCount   int
	SpaceCount int
	OtherCount int
}

func main() {
	//将flower.jpg文件拷贝到abc.jpg
	filePath := "C:/Users/pc/Desktop/1/1.txt"
	srcfile, err := os.Open(filePath)
	if err != nil {
		fmt.Printf("err=%v", err)
		return
	}
	defer srcfile.Close()
	reader := bufio.NewReader(srcfile)
	var count CharCount
	for {
		str, err := reader.ReadString('\n')
		if err == io.EOF {
			break
		}
		for _, v := range str {
			switch {
			case v >= 'a' && v <= 'z':
				fallthrough
			case v >= 'A' && v <= 'Z':
				count.chCount++
			case v == ' ' || v == '\t':
				count.SpaceCount++
			case v >= '0' && v <= '9':
				count.NumCount++
			default:
				count.OtherCount++
			}
		}
	}
	fmt.Printf("字符的个数为=%v 数字的个数为=%v 空格的个数为=%v 其他字符的个数为=%v",
		count.chCount, count.NumCount, count.SpaceCount, count.OtherCount)
}

switch里面要是有判断语句 则switch就不用加条件

兼容中文字符