To simply learn and parse CSV (or TSV) information in Go, you should use two strategies of encoding/csv package deal:
See additionally our instance of methods to write information to a CSV file in Go
Within the examples beneath, we use
information.csvfile:greens,fruits carrot,banana potato,strawberry
Learn all the CSV file directly
On this instance, we open the CSV file, initialize csv.Reader and browse all the information right into a [][]string slice the place the primary index is the file’s line quantity and the second is an index of the comma-separated worth on this line. We are able to do one thing with these information, for instance, convert to an array of structs.
package deal fundamental
import (
"encoding/csv"
"fmt"
"log"
"os"
)
kind ShoppingRecord struct {
Vegetable string
Fruit string
}
func createShoppingList(information [][]string) []ShoppingRecord {
var shoppingList []ShoppingRecord
for i, line := vary information {
if i > 0 { // omit header line
var rec ShoppingRecord
for j, discipline := vary line {
if j == 0 {
rec.Vegetable = discipline
} else if j == 1 {
rec.Fruit = discipline
}
}
shoppingList = append(shoppingList, rec)
}
}
return shoppingList
}
func fundamental() {
// open file
f, err := os.Open("information.csv")
if err != nil {
log.Deadly(err)
}
// keep in mind to shut the file on the finish of this system
defer f.Shut()
// learn csv values utilizing csv.Reader
csvReader := csv.NewReader(f)
information, err := csvReader.ReadAll()
if err != nil {
log.Deadly(err)
}
// convert information to array of structs
shoppingList := createShoppingList(information)
// print the array
fmt.Printf("%+vn", shoppingList)
}
Output:
[{Vegetable:carrot Fruit:banana} {Vegetable:potato Fruit:strawberry}]Learn a CSV file line by line
Studying line by line is much like studying the entire file directly, however on this case, we use csv.Reader.Learn() methodology to learn the subsequent line of information within the infinite loop. This loop is exited when no extra information can be found, i.e., io.EOF error happens.
package deal fundamental
import (
"encoding/csv"
"fmt"
"io"
"log"
"os"
)
func fundamental() {
// open file
f, err := os.Open("information.csv")
if err != nil {
log.Deadly(err)
}
// keep in mind to shut the file on the finish of this system
defer f.Shut()
// learn csv values utilizing csv.Reader
csvReader := csv.NewReader(f)
for {
rec, err := csvReader.Learn()
if err == io.EOF {
break
}
if err != nil {
log.Deadly(err)
}
// do one thing with learn line
fmt.Printf("%+vn", rec)
}
}
Output:
[vegetables fruits]
[carrot banana]
[potato strawberry]Use a non-default discipline delimiter and browse a TSV file
The usual separator for csv.Reader is the comma, nevertheless it’s straightforward to alter it to any rune. As an example, you’ll be able to change it to the tab character t, and on this approach, you get the TSV reader:
