How to read and write data using the encoding/csv package for CSV I/O in Go?

To read and write data using the encoding/csv package in Go, you need to follow these steps:

Import the encoding/csv package.

import (
    "encoding/csv"
    "os"
)

To read data from a CSV file, open the file using os.Open() and create a new csv.Reader using csv.NewReader(). Pass the opened file as an argument to NewReader().

file, err := os.Open("data.csv")
if err != nil {
    // Handle error
}

defer file.Close()

reader := csv.NewReader(file)

Use the Read() method of the csv.Reader to read records from the CSV file. This method returns a slice of strings, where each element represents a field in a CSV record.

for {
    record, err := reader.Read()
    if err == io.EOF {
        break
    }
    if err != nil {
        // Handle error
    }

    // Process the record
    fmt.Println(record)
}

To write data to a CSV file, open the file using os.Create() or os.OpenFile() and create a new csv.Writer using csv.NewWriter(). Pass the opened file as an argument to NewWriter(). You can also specify a custom delimiter or other options when creating the writer.

file, err := os.Create("output.csv")
if err != nil {
    // Handle error
}

defer file.Close()

writer := csv.NewWriter(file)

Use the Write() method of the csv.Writer to write records to the CSV file. The Write() method accepts a slice of strings, where each element represents a field in a CSV record.

record := []string{"John Smith", "43", "Engineer"}
writer.Write(record)

// Call Flush() to ensure the buffered data is written to the file
writer.Flush()

if err := writer.Error(); err != nil {
    // Handle error
}

You can also write multiple records at once using the WriteAll() method. Pass a slice of slices of strings to the WriteAll() method, where each inner slice represents a record.

records := [][]string{
    {"John Smith", "43", "Engineer"},
    {"Jane Doe", "37", "Manager"},
    {"Alice Cooper", "28", "Developer"},
}

writer.WriteAll(records)

// Call Flush() to ensure the buffered data is written to the file
writer.Flush()

if err := writer.Error(); err != nil {
    // Handle error
}

Remember to handle errors appropriately while reading or writing CSV files.