Golang csv 读写案例，及修改文件内容

go 修改csv文件案例，读取文件内容，缓存修改后再覆盖写入

package main

import (
	"encoding/csv"
	"fmt"
	"io"
	"os"
)

func main() {
	WriteCsv()
	//ReadCsv()
	ModifyCsv()
    multiRoutineWriteCsv()
}

func WriteCsv() {
	f, _ := os.Create("test.csv")
	defer f.Close()
	f.WriteString("\xEF\xBB\xBF") //写入utf-8 编码
	w := csv.NewWriter(f)
	w.Write([]string{"网站", "类型"})
	w.Write([]string{"知乎", "问答类"})
	w.Write([]string{"百度", "搜索类"})
	w.Write([]string{"B站", "视频类"})
	w.Flush()
}

func ReadCsv() {
	f, _ := os.Open("test.csv")
	reader := csv.NewReader(f)
	//reader.Comma = ';'
	defer f.Close()
	count := 0
	var record []string
	var err error
	for {
		record, err = reader.Read()
		if err != nil {
			if err == io.EOF {
				err = nil
			}
			break
		}
		count++
		fmt.Printf("%#v \n", record)
	}

	/*f2, _ := os.Open("test.csv")
	reader2 := csv.NewReader(f2)
	record2, _ := reader2.ReadAll()
	fmt.Println(record2)
	f2.Close()*/
}

func ModifyCsv() {
	f, _ := os.Open("test.csv")
	//defer f.Close()
	reader := csv.NewReader(f)
	records, err := reader.ReadAll()
	if err != nil {
		panic(err)
	}
	f.Close()
	fmt.Println(records)
	for i := 0; i < len(records); i++ {
		for j := 0; j < len(records[0]); j++ {
			records[i][j] = records[i][j] + "1"
		}
	}
	//修改二维数组，然后再重新写入，达到修改的目的
	file, err := os.Create("test.csv")
	defer file.Close()
	//file.WriteString("\xEF\xBB\xBF") //写入utf-8 编码
	w := csv.NewWriter(file)
	/*w.Write([]string{"百度1", "搜索类1"})
	w.Write([]string{"B站1", "视频类1"})*/
	w.WriteAll(records)
	w.Flush()
}

func multiRoutineWriteCsv() {
	wg := sync.WaitGroup{}
	f, _ := os.Create("multiGoRoutineTest1.csv")
	defer f.Close()
	f.WriteString("\xEF\xBB\xBF") //写入utf-8 编码
	w := csv.NewWriter(f)
	syncMap := sync.Map{}
	for i := 0; i < 20; i++ {
		wg.Add(1)
		go func(i int, wg *sync.WaitGroup, w *csv.Writer) {
			defer wg.Done()
			syncMap.Store("问答类"+strconv.Itoa(i), i)
			syncMap.Store("类型"+strconv.Itoa(i), i)
			syncMap.Store("知乎"+strconv.Itoa(i), i)
			syncMap.Store("百度"+strconv.Itoa(i), i)
			syncMap.Store("B站"+strconv.Itoa(i), i)
			syncMap.Store("视频类"+strconv.Itoa(i), i)
		}(i, &wg, w)
	}
	wg.Wait()
	syncMap.Range(func(key, value interface{}) bool {
		strings := key.(string)
		w.Write([]string{strings})
		return true
	})
	w.Flush()
}

Go二维数组的排序案例

func Test2Array(t *testing.T) {
	interval := [][]string{
		{strconv.Itoa(rand.Intn(100)), strconv.Itoa(rand.Intn(100))},
		{strconv.Itoa(rand.Intn(100)), strconv.Itoa(rand.Intn(100))},
		{strconv.Itoa(rand.Intn(100)), strconv.Itoa(rand.Intn(100))},
		{strconv.Itoa(rand.Intn(100)), strconv.Itoa(rand.Intn(100))},
	}
	fmt.Println(interval)

	sort.Slice(interval, func(i, j int) bool {
		if interval[i][0] == interval[j][0] {
			return interval[i][1] < interval[j][1]
		} else {
			return interval[i][0] < interval[j][0]
		}
	})

	fmt.Println(interval)
}

执行结果：

[[81 87] [47 59] [81 18] [25 40]]
[[25 40] [47 59] [81 18] [81 87]]