csv

csv2

Parse csv files directly into struct instances.

Quickstart

Parse the csv file:

ID,NAME,ABBREV
1,"United States",US
2,"Canada",CA

package main

import (
    "fmt"
    "os"

    "github.com/aodin/csv2" // Will import as csv!
)

type Country struct {
    ID     int64
    Name   string
    Abbrev string
}

func (c Country) String() string {
    return fmt.Sprintf("%d: %s", c.ID, c.Name)
}

func main() {
    f, err := os.Open("./countries.csv")
    if err != nil {
        panic(err)
    }
    csvf := csv.NewReader(f)

    // Discard the header
    if _, err = csvf.Read(); err != nil {
        panic(err)
    }

    var countries []Country
    if err = csvf.Unmarshal(&countries); err != nil {
        panic(err)
    }
    fmt.Println(countries)
}

Destination Types

Supported field types for destination structs include:

• string
• int64
• float64
• bool
• time.Time

By default, time.Time fields will be parsed with the RFC3339 layout. Alternative layouts can be specified by adding a csv tag to the field:

type holiday struct {
    Name string
    Day  time.Time `csv:"Jan _2"`
}

When a csv column is empty, the types above will error. You will want to use a pointer type, which will be set to nil when there is no content:

• *int64
• *float64
• *bool
• *time.Time

Writer

The package can also write slices of structs to an output, including a header row derived from struct field names!

f, err := os.OpenFile("out.csv", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
    panic(err)
}
defer f.Close()

writer := csv.NewWriter(f)
writer.WriteHeader(&countries)
writer.Marshal(&countries)

ID,Name,Abbrev
1,United States,US
2,Canada,CA

Happy Hacking!

aodin, 2014