xlsxreader

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Here is the code that I have written to read the attached file:

package main

import (
	"bytes"
	"encoding/csv"
	"fmt"
	"log"

	"github.com/thedatashed/xlsxreader"
)

// copy of https://godoc.org/github.com/tealeg/xlsx#ColLettersToIndex
// column is read from the right to left, for each char, res += (n+char-A)*26pow(i) (0<= i <=len(col)-1).
func columnIndex(col string) int {
	sum, mul, n := 0, 1, 0
	for i := len(col) - 1; i >= 0; i, mul, n = i-1, mul*26, 1 {
		c := col[i]
		switch {
		case c >= 'A' && c <= 'Z':
			n += int(c - 'A')
		case c >= 'a' && c <= 'z':
			n += int(c - 'a')
		}
		sum += n * mul
	}
	return sum
}

func getColCount(f *xlsxreader.XlsxFileCloser) int {
	row := <-f.ReadRows(f.Sheets[0])
	if row.Error != nil {
		return 0
	}
	return columnIndex(row.Cells[len(row.Cells)-1].Column) + 1
}

func main() {
	var result []string
	// Create an instance of the reader by opening a target file
	xl, _ := xlsxreader.OpenFile("./file1.xlsx")

	// Ensure the file reader is closed once utilised
	defer xl.Close()
	numColumns := getColCount(xl)
	for row := range xl.ReadRows(xl.Sheets[0]) {
		if row.Error != nil {
			continue
		}
		csvRow := make([]string, numColumns)
		data := make([][]string, 0)
		for _, curCell := range row.Cells {
			colIndex := columnIndex(curCell.Column)
			if colIndex < numColumns {
				csvRow[colIndex] = curCell.Value
			}
		}
		data = append(data, csvRow)
		buf := new(bytes.Buffer)
		w := csv.NewWriter(buf)
		err := w.WriteAll(data)
		if err != nil {
			panic(err)
		}
		if err := w.Error(); err != nil {
			log.Fatalln("error writing csv:", err)
		}
		csvString := buf.String()[:len(buf.String())-1]
		result = append(result, csvString)
	}
	fmt.Println(result)
}

However, When the data from the second row of the L column i.e. the value of the Facebook score is read then it's printed as 4.4000000000000004 instead of 4.4. Why is this rounding error coming in the case of some float-type data?

File_Attached_Here