Struct to CSV data as string without creating CSV file

Question

I have a struct which I want to convert into a CSV string. I don't have to write the CSV file. I just need to create the CSV string.

The Go CSV package (https://golang.org/pkg/encoding/csv/) only provides the writing facility.

Here's the struct:

type myData struct {
    A string `json:"a"`
    B string `json:"b"`
    C string `json:"c"`
}

CSV:

1,2,3
4, ,6

I wanted a CSV string so that I can directly upload the string as a file in cloud storage via a serverless environment. So, I want to avoid creating a file in serverless environment.

Is there any package that can help in doing this?

encoding/csv does what you need. Your assumption that encoding/csv allways creates files is plain wrong. — Volker
– Volker, Commented Apr 6, 2020 at 6:59

Azeem · Accepted Answer · 2025-01-04 05:27:33Z

12

You can use bytes.Buffer to write CSV data and get string using its String() function like this (live):

package main

import (
    "bytes"
    "encoding/csv"
    "fmt"
    "log"
)

func main() {
    data := [][]string{
        {"id", "name"},
        {"123", "ABC"},
        {"456", "XYZ"},
    }

    b := new(bytes.Buffer)
    w := csv.NewWriter(b)

    w.WriteAll(data)
    if err := w.Error(); err != nil {
        log.Fatal(err)
    }

    s := b.String()
    fmt.Println(s)
}

Output:

id,name
123,ABC
456,XYZ

edited Jan 4 at 5:27

answered Apr 6, 2020 at 7:06

Azeem

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Eklavya · Accepted Answer · 2020-04-06 07:35:47Z

6

Use bytes.Buffer to write data without creating file. With bytes.Buffer we can write bytes into a single buffer, and then convert to a string when we are done by invoke the String() func.

var csvData = [][]string{
      {"SuperHero Name", "Power", "Weakness"},
      {"Batman", "Wealth", "Human"},
      {"Superman", "Strength", "Kryptonite"},
   }
buf := new(bytes.Buffer)
wr := csv.NewWriter(buf)
w.WriteAll(csvData)
csvString := buf.String()

edited Apr 6, 2020 at 7:35

answered Apr 6, 2020 at 7:23

Eklavya

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