Creating Workbooks

New Workbook

Create a workbook with the default sheet name (“Sheet1”) or provide a custom name:

wb := werkbook.New()
wb := werkbook.New(werkbook.FirstSheet("Report"))
wb := werkbook.New(
    werkbook.FirstSheet("Report"),
    werkbook.WithDate1904(true),
)

Setting Cell Values

Use SetValue with A1 notation. werkbook accepts Go native types and converts them automatically:

sheet := wb.Sheet("Report")

sheet.SetValue("A1", "Name")       // string
sheet.SetValue("B1", 42)           // int → float64
sheet.SetValue("C1", 3.14)         // float64
sheet.SetValue("D1", true)         // bool
sheet.SetValue("E1", time.Now())   // time.Time -> .xlsx date serial number
sheet.SetValue("F1", nil)          // clears the cell

Supported types: string, bool, int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, float32, float64, time.Time, and nil.

You can also pass an existing werkbook.Value directly.

SetValue clears any previous formula in the target cell. nil produces an empty cell value.

float32 and float64 values must be finite. NaN and Inf are rejected as ErrUnsupportedType.

Adding Formulas

Set formulas without the leading =:

sheet.SetFormula("A5", "SUM(A2:A4)")
sheet.SetFormula("B5", "AVERAGE(B2:B4)")
sheet.SetFormula("C1", "IF(A1>100,\"High\",\"Low\")")

Formulas are evaluated lazily when you call GetValue, or you can force evaluation of all formulas:

wb.Recalculate()

This is usually only necessary if you want every dirty formula computed immediately before saving or serializing.

Working with Multiple Sheets

wb := werkbook.New(werkbook.FirstSheet("Summary"))

// Add more sheets
dataSheet, _ := wb.NewSheet("Data")
chartsSheet, _ := wb.NewSheet("Charts")

// Reference across sheets
summary := wb.Sheet("Summary")
summary.SetFormula("A1", "SUM(Data!B2:Data!B100)")
summary.SetFormula("A2", "AVERAGE(Data!C2:Data!C100)")

// List all sheets
for _, name := range wb.SheetNames() {
    fmt.Println(name)
}

// Remove a sheet
wb.DeleteSheet("Charts")

Additional sheet operations:

wb.SetSheetName("Data", "Transactions")
wb.SetSheetVisible("Transactions", false)

summary := wb.Sheet("Summary")
fmt.Println(summary.Visible()) // true

You cannot delete the last remaining sheet.

Column Width and Row Height

sheet.SetColumnWidth("A", 20.0)
sheet.SetColumnWidth("B", 15.5)

sheet.SetRowHeight(1, 30.0) // header row

Merged Cells, Tables, and Named Ranges

The library also supports higher-level workbook authoring features:

sheet.MergeCell("A1", "D1")

sheet.AddTable(werkbook.Table{
    DisplayName: "SalesTable",
    Ref:         "A1:D10",
})

wb.SetDefinedName(werkbook.DefinedName{
    Name:         "SalesTotal",
    Value:        "Summary!$D$10",
    LocalSheetID: -1,
})

These features are covered in more detail in Workbook Operations and Tables and Named Ranges.

Saving or Streaming

Write the workbook to disk:

err := wb.SaveAs("report.xlsx")
if err != nil {
    log.Fatal(err)
}

Or write to any io.Writer:

// Using the workbook value you already built:
var buf bytes.Buffer
if err := wb.WriteTo(&buf); err != nil {
    log.Fatal(err)
}

Full Example

package main

import (
    "bytes"
    "fmt"
    "log"
    "time"

    "github.com/jpoz/werkbook"
)

func main() {
    wb := werkbook.New(werkbook.FirstSheet("Inventory"))
    sheet := wb.Sheet("Inventory")

    // Headers
    headers := []string{"Item", "Quantity", "Unit Price", "Total", "Updated"}
    for i, h := range headers {
        col := werkbook.ColumnNumberToName(i + 1)
        sheet.SetValue(col+"1", h)
    }

    // Data rows
    type item struct {
        name  string
        qty   int
        price float64
    }
    items := []item{
        {"Laptop", 10, 999.99},
        {"Monitor", 25, 349.50},
        {"Keyboard", 100, 49.99},
    }

    for i, it := range items {
        row := i + 2
        r := fmt.Sprint(row)
        sheet.SetValue("A"+r, it.name)
        sheet.SetValue("B"+r, it.qty)
        sheet.SetValue("C"+r, it.price)
        sheet.SetFormula("D"+r, fmt.Sprintf("B%d*C%d", row, row))
        sheet.SetValue("E"+r, time.Now())
    }

    // Summary
    sheet.SetValue("A6", "Grand Total")
    sheet.SetFormula("D6", "SUM(D2:D4)")

    // Column widths
    sheet.SetColumnWidth("A", 15)
    sheet.SetColumnWidth("D", 12)
    sheet.SetColumnWidth("E", 18)

    var preview bytes.Buffer
    if err := wb.WriteTo(&preview); err != nil {
        log.Fatal(err)
    }

    if err := wb.SaveAs("inventory.xlsx"); err != nil {
        log.Fatal(err)
    }
}