Excel
Converting Excel to Parquet for Faster Analytics Loads
Convert an Excel workbook to Parquet with pandas or DuckDB, fix column types first, write one file per sheet and check counts so analytics loads run fast.
7 min read
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Excel
Converting Excel to YAML Config Files Without Surprises
Turn an Excel sheet of settings or tables into YAML in Python: shape the data, avoid the Norway problem and number traps, dump safely and validate.
7 min read
Excel
Converting Excel to XML With a Python Script Safely
Convert an Excel sheet to XML in Python: valid element names, escaping, elements versus attributes, encoding, large files and validation against a schema.
7 min read
Excel
Converting Excel to JSON With Python for Clean Output
Convert an Excel sheet to JSON in Python: records, nested groups and JSON Lines, with typed values, ISO dates, nulls and a check that nothing was lost.
6 min read
Excel
Checking an Excel Upload Before Reading It Into Code
Check an Excel upload before parsing: size, name, zip signature, required parts, macro parts, sheet names and header row, in a fixed order with clear errors.
7 min read
Excel
Password Protected Excel Files and Scripts That Read Them
Read password protected Excel files from a script with msoffcrypto-tool, tell file encryption from sheet protection, and keep passwords out of code and logs.
7 min read
Excel
Zip Bombs and Oversized XLSX Uploads and Limits That Work
Stop zip bombs and oversized xlsx uploads with limits on file size, entry count, expansion ratio and rows, enforced before parsing and sized from real files.
7 min read
Excel
Opening Untrusted Excel Files Safely in a Pipeline
Open untrusted Excel files in a sandboxed worker with no network, memory and time limits, a read-only parser and no desktop Excel, then load results as data.
7 min read
Excel
Removing Personal Data From an Excel File Before Sharing
Remove personal data from an Excel file before sharing: drop author properties, mask or delete columns, clear comments and rebuild a clean copy by script.
7 min read
Excel
Hidden Sheets and Metadata Leaking Out of Shared Workbooks
Find hidden sheets, document properties, comments, defined names and pivot caches in a workbook before you share it, with a script that audits the file.
7 min read
Excel
Macros and Why Data Teams Should Block Them by Default
Compare xlsx, xlsm, xls and xlsb for data work, and set a policy that blocks macros by default while allowing reviewed exceptions with a real owner.
7 min read
Excel
Formula Injection in Excel Exports and How to Stop It
Stop formula injection in xlsx exports: write user text as strings with openpyxl or XlsxWriter, neutralize leading =, +, - and @ characters, and test it.
7 min read
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