● Covered by 1 source · 1 reportLow impact1 negative
Analysis of Difficulties Parsing Japan Post's ken_all.csv Postal Code Data
Key points
- Japan Post's ken_all.csv contains parenthetical notes in data fields.
- Lines with long neighborhood or katakana fields are split into multiple rows.
- Split lines duplicate other fields and break at seemingly random points.
- These formatting choices complicate programmatic parsing of the data.
Challenges with Japan Post's CSV
Japan Post's ken_all.csv, a widely used source for Japanese postal code data, presents significant parsing difficulties for developers. The file includes parenthetical notes within data fields, which are irrelevant for programmatic use and complicate data extraction.
These parentheticals often refer to the order of rows, making individual rows less useful when processed in isolation. A standard CSV format would typically use a separate field for such notes.
Unusual Line Splitting
A major issue is the CSV's method for handling overly long fields. If a neighborhood name exceeds 38 characters or a half-width katakana pronunciation field exceeds 76 characters, the line is split into multiple rows. In these split lines, the long field continues, while all other fields are duplicated.
The motivation for this specific formatting is unclear, and it is an uncommon practice in CSV files. The article notes that line breaks in long fields do not occur at character limits or word boundaries, adding to the parsing complexity.
Impact on Developers
These formatting quirks make the ken_all.csv file notoriously difficult to parse programmatically. Developers frequently express frustration with the file's structure, which deviates from standard CSV practices.
The issues highlight a need for more standardized and machine-readable data formats from official sources to facilitate easier integration and use by the tech community.
✨ This summary was generated by AI from the outlets' reporting listed below. It is not independently verified and may contain errors — check the original sources. How BrevFeed works →
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Primary sources
GitHub polm/posutoReporting from
The article details the challenges developers face when parsing the Japan Post's ken_all.csv file, which contains Japanese postal code data. The CSV's unusual formatting, including parenthetical notes and line splitting for long fields, makes automated processing difficult.