Keep the leading zeros of a string when exporting to CSV in Golang-CodePudding

I have a Go application using Gin framework that exports a struct to CSV. One column userCode requires the exported field keeping all the leading zeros of the string.

For example, for string such as 000001, 010101, 000000, the exported field in CSV should have the exact similar value. However, if I directly append the string to the row and write to the buffer, the exported field will emit all the leading zeros and the value becomes: 1, 10101, , I did some digging and it seems this problem can be fixed by setting column type in Excel when reading the csv file, but I was wondering if this can be solved within Go program? Thanks!

My CSV export related function:

func (h *HandleManager) ExportUsers() gin.HandlerFunc {

        var buf bytes.Buffer
        writer := csv.NewWriter(&buf)
        var cols = []string{"User Name", ..., ....}
        writer.Write(cols)
        for _, e := range users {
            var row []string
            // ....
            row = append(row, e.userCode) // type: string
            if err := writer.Write(row); err != nil {
                log.Errorff(h.logCtx, "ExportUsers|WriteToCSV|err:%v", err)
                c.AbortWithStatus(http.StatusInternalServerError)
                return
            }
        }
        writer.Flush()
        c.Writer.Header().Set("Content-Type", "text/csv")
        c.Writer.Header().Set("Content-Disposition", "attachment;filename=" csvFileName ".csv")
        c.Writer.Write(buf.Bytes())
}

CodePudding user response：

After a few tries I found the solution that worked in golang,thanks to the link @Steffen Ullrich posed. Similar to which worked in VB, instead of two quotation marks on both sides, one should be enough:

row = append(row, "=\"" e. userCode  "\"")

will contain all the leading zeros in the CSV file:

000001, 010101, 000000

CodePudding user response：

I tested your code, and the result in excel would loss the zeros, but in txt reader would not;

code:

func main() { type user struct { Name string Code string }

 http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
     var buf bytes.Buffer
     writer := csv.NewWriter(&buf)
     var cols = []string{"Name", "Code"}
     writer.Write(cols)
     users := []user{{Name: "Tome", Code: "001"}, {Name: "James", Code: "000"}}

     for _, e := range users {
         err := writer.Write([]string{e.Name, e.Code})
         if err != nil {
             log.Fatalln(err)
         }
     }
     writer.Flush()
     w.Header().Set("Content-Type", "text/csv")
     w.Header().Set("Content-Disposition", "attachment;filename=" "test.csv")

     w.Write(buf.Bytes())

 })

 http.ListenAndServe(":8080", nil)

}

result：