ID Column Uniqueness Check
Check exact string ID uniqueness in a supplied column, treating empty strings and leading zeros literally; report indices of occurrences after each first occurrence.
Description
An identifier column is unique when each stored string occurs only once.
An identifier column is unique when each stored string occurs only once. Treating identifiers as exact text preserves leading zeros, case and whitespace that numeric or normalized comparisons could discard.1
Check exact string ID uniqueness in a supplied column, treating empty strings and leading zeros literally; report indices of occurrences after each first occurrence.
When to use ID Column Uniqueness Check
Use this tool to check exact string ID uniqueness in a supplied column, treating empty strings and leading zeros literally; report indices of occurrences after each first occurrence.
Choose the original CSV text, decoded cell strings, byte values or counts requested by this tool. Use the stated delimiter, encoding, indexing and number/date convention.
How to use ID Column Uniqueness Check and understand its results
- Choose the original CSV text, decoded cell strings, byte values or counts requested by this tool. Use the stated delimiter, encoding, indexing and number/date convention.
- Enter values using the field table and calculation rules, then run the tool.
- Read unique, distinctCount, duplicateIndices. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| values | Values | list of string; maximum length: 10000; minimum entries: 0; maximum entries: 10000 | Required |
Supply the identifier strings in row order. The tool inserts each value into a set and records the zero-based position whenever that exact value was already seen. Thus duplicateIndices contains later occurrences, not the first member of each group. Empty strings are ordinary keys; an empty list is unique with distinctCount 0.
distinctCount = size of the exact-string set; unique = duplicateIndices is empty Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| unique | Unique | boolean |
| distinctCount | Distinct count | integer; minimum: 0; maximum: 9007199254740991 |
| duplicateIndices | Duplicate indices | list of integer; minimum: 0 |
{
"input": {
"values": [
"001",
"1",
"001"
]
},
"output": {
"unique": false,
"distinctCount": 2,
"duplicateIndices": [
2
]
}
}Limitations and assumptions
No trimming, case folding or numeric conversion occurs. This does not impose a nonblank-key rule, detect duplicates across unsupplied files, or establish database constraints. Choose any normalization policy before running the check.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Cell-string lists also have a combined text budget of 100,000 UTF-16 units per list. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.
Alternative or Complementary methods
Use Foreign-Key Pair Match Rate: Measure the fraction of child key occurrences present in an exact parent-key set, counting repeated children individually and treating empty strings literally; no children returns hasChildren false and rate zero. For a complementary task, use Duplicate Header Detector: Find exact case-sensitive duplicate header names with all zero-based positions, without trimming or changing header text.
References
-
ID Column Uniqueness Check — tool.io
Similar or alternative tools
- Foreign-Key Pair Match Rate
Measure the fraction of child key occurrences present in an exact parent-key set, counting repeated children individually and treating empty strings literally; no children returns hasChildren false and rate zero.
- Duplicate Header Detector
Find exact case-sensitive duplicate header names with all zero-based positions, without trimming or changing header text.