Load CSV files in Go

This is a very easy way to open a CSV file line by line in Go. Suppose we have a CSV file pops.csv that looks like this

To read the file line by line,

package main

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

type CityPopulation struct {
	City  string
	Population string
}

func check(e error) {
	if e != nil {
		panic(e)
	}

}

func main() {
	fmt.Println("This is the entry point!")

	file, err := os.Open("pops.csv")
	check(err)
	println("Log: Opened CSV file")

	reader := csv.NewReader(file)

	var pops []CityPopulation

	for {
		line, err := reader.Read()

		if err == io.EOF {
			break
		}
		check(err)

		pops = append(pops, CityPopulation{
			City:  line[0],
			Population: line[1],
		})
	}
	for i := range pops {
        fmt.Printf("The city of %s is populated with %s people.\n" , pops[i].City, pops[i].Population)
	}
}

We created a struct CityPopulation to hold the values of the CSV. Then we created a function check(e error) to check for errors. The function only checks for errors in the file an panics.

In the main function, we use os.Open("pops.csv") to open the CSV file and load it. We then use csv.NewReader() to create a reader. We then use a for loop to read the file line by line. Notice the io.EOF, it is emitted by reader.Read() when it gets to the end of the CSV file. We then load the contents of the line into the pops slice that was created earlier.