Declared CSV Calendar Date Parser
Validate imported date-only columns against an explicit fixed pattern and preserve invalid-date evidence.
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How to use Declared CSV Calendar Date Parser
Resolve day/month order through a chosen source pattern instead of a permissive date parser. Exact Gregorian checks reject impossible dates and retain each original cell beside its canonical date and explicit status.
- Enter input, selected columns json, exact missing tokens json, new column suffix.
- Choose the settings for declared csv calendar date parser, then run the tool.
- Review the result and any limitations before copying or downloading it.
Good to know
- 5,000 records, 10 selected date columns, 200,000 CSV characters and Gregorian years 1–9999. Output cell text is capped at 350,000 characters before CSV serialization.
- Four complete date-only patterns with fixed digit widths. No natural language, date-time input, inferred century, time zone or calendar conversion; impossible dates are never normalized into another month.
- Processing is local. Output is limited to 1,000,000 text characters unless a stricter file limit is stated.
Common questions
Can the parser infer whether 03/04 means March 4 or April 3?
No. Choose the explicit source pattern. That same rule applies to every selected cell, and mismatches are reported or refused according to your policy.
Is this input sent to a server?
No. The application processes this input inside your browser tab and does not save it to persistent storage.
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