Python Programming/Excel

Python has multiple 3rd party libraries for reading and writing Microsoft Excel spreadsheet files, including .xls and .xlsx.

For working with .xls files, there is xlrd for reading and xlwt for writing.

For working with .xlsx files, there is xlrd for reading, openpyxl for reading and writing, and XlsxWriter and PyExcelerate for writing.

To interact with the Excel application and create Python-based add-ins: xlwings, xlOil, PyXLL (commercial).

xlrd

Supports reading .xls Excel files. Support for .xlsx files was removed in xlrd version 2.0.0 from Dec 2020 due to security concerns, but is still available in xlrd version 1.2.0 from Dec 2018. License: BSD.

Example: 

import xlrd
workbook = xlrd.open_workbook("MySpreadsheet.xls")
#for sheet in workbook.sheets(): # Loads all the sheets, unlike workbook.sheet_names()
for sheetName in workbook.sheet_names(): # Sheet iteration by name
  print("Sheet name:", sheetName)
  sheet = workbook.sheet_by_name(sheetName)
  for rowno in range(sheet.nrows):
    for colno in range(sheet.ncols):
      cell = sheet.cell(rowno, colno)
      print(str(cell.value)) # Output as a string
      if cell.ctype == xlrd.XL_CELL_DATE:
        dateTuple = xlrd.xldate_as_tuple(cell.value, workbook.datemode)
        print(dateTuple) # E.g. (2017, 1, 1, 0, 0, 0)
        mydate = xlrd.xldate.xldate_as_datetime(cell.value, workbook.datemode)
        print(mydate) # In xlrd 0.9.3
      print()
    
for sheetno in range(workbook.nsheets): # Sheet iteration by index
  sheet = workbook.sheet_by_index(sheetno)
  print("Sheet name:", sheet.name)
  for notekey in sheet.cell_note_map: # In xlrd 0.7.2
    print("Note AKA comment text:", sheet.cell_note_map[notekey].text)
  
print(xlrd.formula.colname(1)) # Column name such as A or AD, here 'B'

Links:

xlwt

Supports writing .xls files. License: BSD.

Links:

openpyxl

Supports reading and writing .xlsx Excel files. Does not support .xls files. License: MIT.

Reading a workbook: 

from openpyxl import load_workbook
workbook = load_workbook("MyNewWorkbook.xlsx")
for worksheet in workbook.worksheets:
  print("==%s==" % worksheet.title)
  for row in worksheet: # For each cell in each row
    for cell in row:
      print(cell.row, cell.column, cell.value) # E.g. 1 A Value
  for cell in worksheet["A"]: # For each cell in column A
    print(cell.value)
  print(worksheet["A1"].value) # A single cell
  print(worksheet.cell(column=1, row=1).value) # A1 value as well

Creating a new workbook: 

from openpyxl import Workbook
workbook = Workbook()
worksheet = workbook.worksheets[0]
worksheet['A1'] = 'String value'
worksheet['A2'] = 42 # Numerical value
worksheet.cell(row=3, column=1).value = "New A3 Value"
workbook.save("MyNewWorkbook.xlsx") # Overrides if it exists

Changing an existing workbook: 

from openpyxl import load_workbook
workbook_name = 'MyWorkbook.xlsx'
workbook = load_workbook(workbook_name)
worksheet = workbook.worksheets[0]
worksheet['A1'] = "String value"
workbook.save(workbook_name)

Links:

XlsxWriter

Supports writing of .xlsx files. License: BSD.

Links:

PyExcelerate

Supports writing .xlsx files. License: BSD.

Links:

xlutils

Supports various operations and queries on .xls files; depends on xlrd and xlwt. License: MIT.

Links:

xlOil

Supports creation of Python-based Excel add-ins. Requires Python 3.6 or later; requires Excel 2010 or later installed. Supports: global and local scope worksheet functions, ribbon customisation, custom task panes, RTD/async functions, numpy, matplotlib, pandas, jupyter. Low overhead function calls due to use of the Excel's C-API and embedded in-process Python

Examples:

Create a function to add one day to a date: 

import datetime as dt
@xloil.func
def pyTestDate(x: dt.datetime) -> dt.datetime:
    return x + dt.timedelta(days=1)

Create a function which give a live ticking clock in an cell (uses RTD): 

@xloil.func
async def pyTestAsyncGen(secs):
    while True:
        await asyncio.sleep(secs)
        yield datetime.datetime.now()

Links:

PyXLL

Professional solution for creating high performance, fully featured, Excel add-ins entirely in Python. Supports all major Python releases from 2.3 to 3.14 and later, and all versions of Excel for Windows (both 64 and 32 bit) including Office 365 from Office 2003.

Widely used in the finance industry to expose quant and risk models to Excel users, as well as many other scientific industries. Originally released in 2010, PyXLL was the first mainstream Python based Excel add-in.

Features include: fast worksheet functions and macros (UDFs) with a flexible type system; built in support for pandas, polars and numpy types; real time data (RTD) functions, using threads or asyncio; easy development with automatic module reloading; interactive and static charts using matplotlib, seaborn, plotly, bokeh and altair (others can be added via extensions); integrated Jupyter notebooks; ribbon customization; custom task panes using wxPython, PySide, PyQt and tkinter; custom deployment options.

from pyxll import xl_func

# Adding '@xl_func' to a Python function makes it callable from Excel.
@xl_func
def hello(name: str) -> str:
    return f"Hello, {name}"

Links:

  • www.pyxll.com

pywin32

Supports access to Windows applications via Windows Component Object Model (COM). Thus, on Windows, if Excel is installed, PyWin32 lets you call it from Python and let it do various things. You can install PyWin32 by downloading a .exe installer from SourceForge, where it is currently hosted.

Links:

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