Excel Spreadsheets

Excel Spreadsheets

Read and write Microsoft Excel files (.xlsx). Create workbooks, manage sheets, read cell values, and generate reports with formatting support.

Loading

local excel = require("excel")

Creating Workbooks

New Workbook

Creates a new empty Excel workbook.

local wb, err = excel.new()
if err then
    return nil, err
end

-- Create sheets and add data
wb:new_sheet("Report")
wb:set_cell_value("Report", "A1", "Title")

wb:close()

Returns: Workbook, error

Open Workbook

Opens an Excel workbook from a reader object.

local fs = require("fs")

local vol, err = fs.get("app:data")
if err then
    return nil, err
end

local file, err = vol:open("/reports/sales.xlsx", "r")
if err then
    return nil, err
end

local wb, err = excel.open(file)
if err then
    file:close()
    return nil, err
end

-- Read data from workbook
local rows = wb:get_rows("Sheet1")
for i, row in ipairs(rows) do
    print("Row " .. i .. ": " .. table.concat(row, ", "))
end

wb:close()
file:close()

Parameter	Type	Description
reader	File	Must implement io.Reader (e.g., fs.File)

Returns: Workbook, error

Sheet Operations

Create Sheet

Creates a new sheet or returns existing sheet index.

local wb = excel.new()

-- Create sheets
local idx1 = wb:new_sheet("Summary")
local idx2 = wb:new_sheet("Details")
local idx3 = wb:new_sheet("Charts")

-- If sheet exists, returns its index
local existing = wb:new_sheet("Summary")  -- returns same as idx1

Parameter	Type	Description
name	string	Sheet name

Returns: integer, error

List Sheets

Returns list of all sheet names in workbook.

local wb = excel.new()
wb:new_sheet("Sales")
wb:new_sheet("Expenses")
wb:new_sheet("Summary")

local sheets = wb:get_sheet_list()
-- sheets = {"Sheet1", "Sales", "Expenses", "Summary"}

for _, name in ipairs(sheets) do
    print("Sheet:", name)
end

Returns: string[], error

Cell Operations

Set Cell Value

Sets value of a single cell.

local wb = excel.new()
wb:new_sheet("Data")

-- Set different value types
wb:set_cell_value("Data", "A1", "Product Name")  -- string
wb:set_cell_value("Data", "B1", "Price")         -- string
wb:set_cell_value("Data", "C1", "In Stock")      -- string

wb:set_cell_value("Data", "A2", "Widget")
wb:set_cell_value("Data", "B2", 29.99)           -- number
wb:set_cell_value("Data", "C2", true)            -- boolean

wb:set_cell_value("Data", "A3", "Gadget")
wb:set_cell_value("Data", "B3", 49.99)
wb:set_cell_value("Data", "C3", false)

-- Cell references support columns beyond Z
wb:set_cell_value("Data", "AA1", "Extended Column")
wb:set_cell_value("Data", "AB100", "Far cell")

Parameter	Type	Description
sheet	string	Sheet name
cell	string	Cell reference (“A1”, “B2”, “AA100”)
value	any	string, integer, number, or boolean

Returns: error

Get All Rows

Gets all rows from a sheet as 2D array.

local wb = excel.new()
wb:new_sheet("Report")
wb:set_cell_value("Report", "A1", "Name")
wb:set_cell_value("Report", "B1", "Score")
wb:set_cell_value("Report", "A2", "Alice")
wb:set_cell_value("Report", "B2", 95)
wb:set_cell_value("Report", "A3", "Bob")
wb:set_cell_value("Report", "B3", 87)

local rows, err = wb:get_rows("Report")
if err then
    return nil, err
end

-- rows[1] = {"Name", "Score"}
-- rows[2] = {"Alice", "95"}
-- rows[3] = {"Bob", "87"}

for i, row in ipairs(rows) do
    if i == 1 then
        print("Headers:", row[1], row[2])
    else
        print("Data:", row[1], "scored", row[2])
    end
end

Parameter	Type	Description
sheet	string	Sheet name

Returns: string[][], error

All cell values returned as strings. Booleans as “TRUE” or “FALSE”, numbers as string representation.

File Operations

Write to File

Writes workbook to a writer object.

local fs = require("fs")
local wb = excel.new()

-- Build report
wb:new_sheet("Monthly Report")
wb:set_cell_value("Monthly Report", "A1", "Month")
wb:set_cell_value("Monthly Report", "B1", "Revenue")
wb:set_cell_value("Monthly Report", "A2", "January")
wb:set_cell_value("Monthly Report", "B2", 45000)
wb:set_cell_value("Monthly Report", "A3", "February")
wb:set_cell_value("Monthly Report", "B3", 52000)

-- Write to file
local vol, err = fs.get("app:output")
if err then
    wb:close()
    return nil, err
end

local file, err = vol:open("/reports/monthly.xlsx", "w")
if err then
    wb:close()
    return nil, err
end

local err = wb:write_to(file)
file:close()
wb:close()

if err then
    return nil, err
end

Parameter	Type	Description
writer	File	Must implement io.Writer (e.g., fs.File)

Returns: error

Close Workbook

Closes workbook and releases resources.

local wb = excel.new()
-- ... work with workbook ...
wb:close()

-- Safe to call multiple times
wb:close()

Returns: error

Errors

Condition	Kind	Retryable
No context	errors.INTERNAL	no
Invalid workbook	errors.INVALID	no
Workbook closed	errors.INTERNAL	no
Not a reader/writer	errors.INTERNAL	no
Invalid Excel file	errors.INTERNAL	no
Non-existent sheet	errors.INTERNAL	no
Invalid cell reference	errors.INTERNAL	no
Write failed	errors.INTERNAL	no

See Error Handling for working with errors.

See Also

• Filesystem - File operations for reading/writing Excel files