xlsxlisted

# Excel workbooks (.xlsx) **openpyxl** for anything that reads or edits. **XlsxWriter** only when writing a very large file from scratch, where it is faster and lighter but cannot read. The single fact that causes the most wasted time: > **openpyxl does not calculate.** Writing `=SUM(B2:B10)` stores the formula > string. The cached *value* stays empty until a real spreadsheet application > opens and recalculates the file. `load_workbook(data_only=True)` returns > `None` for every formula cell in a file that Excel has never opened. So: if the user needs a workbook whose numbers are readable by other tools, run `scripts/recalc.py` after writing it. If you need to read values from a file someone sent you, `data_only=True` works — Excel already cached them. ## Before editing a workbook, look at it scripts/inspect_xlsx.py budget.xlsx Prints each sheet with its dimensions, frozen panes, column widths, a preview grid, where the formulas are, merged ranges, named ranges, conditional formatting and charts. **Do this first on any file you did not create** — a spreadsheet's structure is rarely what the file name suggests. scripts/inspect_xlsx.py budget.xlsx --sheet Q1 --range A1:F20 # focus scripts/inspect_xlsx.py budget.xlsx --formulas # every formula ## Creating a workbook ```python from openpyxl import Workbook from openpyxl.styles import Font, Alignment, PatternFill, Border, Side from openpyxl.utils import get_column_letter wb = Workbook() w