Guide Warns Against Silent Data Loss When Merging CSV Files

A technical guide explains why merging a folder of CSV files can go wrong even when the operation appears to succeed. It highlights encoding problems, since a CSV's character encoding depends on the exporting application, and recommends strict decoding rather than options that silently discard bytes. The article also covers byte-order marks and inconsistent column names, noting that differing headers can create separate columns or duplicate labels unless aliases are approved and checked. It further cautions that positional appending can misplace values when headers shift, and that label-aligned concatenation does not by itself enforce a schema. The piece closes with a Python workflow that rejects unexpected schema differences and avoids re-ingesting a previous output file.