openpyxl add formula in cell code example

Example: openpyxl new workbook

>>> from openpyxl import Workbook
>>> from openpyxl.utils import get_column_letter
>>>
>>> wb = Workbook()
>>>
>>> dest_filename = 'empty_book.xlsx'
>>>
>>> ws1 = wb.active
>>> ws1.title = "range names"
>>>
>>> for row in range(1, 40):
...     ws1.append(range(600))
>>>
>>> ws2 = wb.create_sheet(title="Pi")
>>>
>>> ws2['F5'] = 3.14
>>>
>>> ws3 = wb.create_sheet(title="Data")
>>> for row in range(10, 20):
...     for col in range(27, 54):
...         _ = ws3.cell(column=col, row=row, value="{0}".format(get_column_letter(col)))
>>> print(ws3['AA10'].value)
AA
>>> wb.save(filename = dest_filename)