Hi this is my first go program and I am looking for some feedback and help
writing buffer to csv. To give you an idea of the structure of the data I
have run head on the input file gives output seen at the bottom.
package main
import (
"bytes"
"encoding/csv"
"fmt"
"io"
"log"
"strconv"
"strings"
"bufio"
"io/ioutil"
)
// Calculate economic block value given a 40x20x12 block of density sg and grade
func calculateE(sg float64, grade float64) float64 {
return 40 * 20 * 12 * sg * grade * 80 / 10 * 0.66
}
// Credit: Stack Overflow
func processCSV(rc io.Reader) (ch chan []string) {
ch = make(chan []string, 10)
go func() {
r := csv.NewReader(rc)
if _, err := r.Read(); err != nil { //read header
log.Fatal(err)
}
defer close(ch)
for {
rec, err := r.Read()
if err != nil {
if err == io.EOF {
break
}
log.Fatal(err)
}
ch <- rec
}
}()
return
}
// Credit: Stack Overflow
func Readln(r *bufio.Reader) (string, error) {
var (
isPrefix bool = true
err error = nil
line, ln []byte
)
for isPrefix && err == nil {
line, isPrefix, err = r.ReadLine()
ln = append(ln, line...)
}
return string(ln), err
}
func main() {
var buf bytes.Buffer
w := csv.NewWriter(&buf)
file := "C:/ORIG.csv"
dat, _ := ioutil.ReadFile(file)
f := string(dat)
for rec := range processCSV(strings.NewReader(f)) {
sg, err := strconv.ParseFloat(rec[17], 64)
grade, err := strconv.ParseFloat(rec[13], 64)
if grade < 0 {
grade = 0
} else {
grade = 0.1*grade
}
if sg < 0 {
sg = 0
}
fmt.Println(grade)
// get economic block value
e := calculateE(sg, grade)
gradeStr := strconv.FormatFloat(grade, 'f', 8, 64)
sgStr := strconv.FormatFloat(sg, 'f', 8, 64)
eStr := strconv.FormatFloat(e, 'f', 8, 64)
rec := append(rec[0:4], eStr, sgStr, gradeStr)
if err = w.Write(rec); err != nil {
log.Fatal(err)
}
}
w.Flush()
if err := w.Error(); err != nil {
log.Fatal(err)
}
//fmt.Println(buf.String())
//f2, err := os.Create("C:/Users/root/result.csv")
//defer f2.Close()
//writer := csv.NewWriter(f2)
//writer.Write(buf.String())
}
// 500mb csv with head of the data looks like:
const data =
`xcentre,ycentre,zcentre,xlength,ylength,zlength,fe_percent,fe_recovery,oxide,rescat,sg,mat_type_8,fillpc,mass_recovery,mass_recovery_percent,air,al2o3,cao,k2o,loi,mgo,mno,phos,sio2,tio2
556960.000,6319980.000,-1100.000,40.000,20.000,12.000,-99.00000000,66.00000000,-99,4,2.84999990,2,91,0.00000000,0.00000000,0,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000
557000.000,6319980.000,-1100.000,40.000,20.000,12.000,-99.00000000,66.00000000,-99,4,2.84999990,2,91,0.00000000,0.00000000,0,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000
556960.000,6320000.000,-1100.000,40.000,20.000,12.000,-99.00000000,66.00000000,-99,4,2.84999990,2,91,0.00000000,0.00000000,0,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000
557000.000,6320000.000,-1100.000,40.000,20.000,12.000,-99.00000000,66.00000000,-99,4,2.84999990,2,91,0.00000000,0.00000000,0,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000
556960.000,6319980.000,-1088.000,40.000,20.000,12.000,-99.00000000,66.00000000,-99,4,2.84999990,2,100,0.00000000,0.00000000,0,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000
557000.000,6319980.000,-1088.000,40.000,20.000,12.000,-99.00000000,66.00000000,-99,4,2.84999990,2,100,0.00000000,0.00000000,0,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000
556960.000,6320000.000,-1088.000,40.000,20.000,12.000,-99.00000000,66.00000000,-99,4,2.84999990,2,100,0.00000000,0.00000000,0,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000
557000.000,6320000.000,-1088.000,40.000,20.000,12.000,-99.00000000,66.00000000,-99,4,2.84999990,2,100,0.00000000,0.00000000,0,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000
557040.000,6319980.000,-1100.000,40.000,20.000,12.000,-99.00000000,66.00000000,-99,4,2.84999990,2,91,0.00000000,0.00000000,0,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000,0.00000000
`
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