Here is an answer for Python 3.8 and OpenPyXL 3.0.0.
I tried to avoid using the get_column_letter
function but failed.
This solution uses the newly introduced assignment expressions aka "walrus operator":
import openpyxl
from openpyxl.utils import get_column_letter
workbook = openpyxl.load_workbook("myxlfile.xlsx")
worksheet = workbook["Sheet1"]
MIN_WIDTH = 10
for i, column_cells in enumerate(worksheet.columns, start=1):
width = (
length
if (length := max(len(str(cell_value) if (cell_value := cell.value) is not None else "")
for cell in column_cells)) >= MIN_WIDTH
else MIN_WIDTH
)
worksheet.column_dimensions[get_column_letter(i)].width = width