Description
Test value for exact emptiness and code for one lowercase ASCII letter or digit.
Catalog identifiers and labels follow local formatting conventions. Splitting or recognizing a token's shape preserves structure without establishing that its identifier or classification is valid.
Test value for exact emptiness and code for one lowercase ASCII letter or digit.
When to use this tool
Use MARC Subfield Empty Value Flag when you need one explicit catalog-label parsing or formatting step.
How to use the tool and how it works
- Enter code, value. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read empty, validCodeShape. Inspect empty, validCodeShape before interpreting the associated values.
Test value for exact emptiness and code for one lowercase ASCII letter or digit. Return the flags independently.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| code | Code | Required. Text; maximum UTF-16 length 8192. |
| value | Value | Required. Text; maximum UTF-16 length 8192. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| empty | Whether the represented collection or span has no occupied elements. | Required. Boolean. |
| validCodeShape | Valid Code Shape | Required. Boolean. |
{
"input": {
"code": "a",
"value": ""
},
"output": {
"empty": true,
"validCodeShape": true
}
}Limitations and assumptions
- Whitespace is not empty; this checks a subfield-code shape rather than complete MARC syntax or field-specific validity.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
Alternative or Complementary methods
Consult the cataloging scheme and source record before assigning semantic meaning or a filing order.
References
Similar or alternative tools
- MARC Fixed Field Single Position Extractor
Return the character at that position.
- Catalogue Field Repeat Count
Count exact requestedTag matches in tags and return max(0, occurrences - 1) as repeatsBeyondFirst.