Adjacent Change Indexes

Return indexes whose value differs from the previous supplied string, not CSS change hints or a value transform.

Description

Return indexes whose value differs from the previous supplied string, not CSS change hints or a value transform.

Adjacent change indexes mark the first position after each change in a sequence. They offer a compact boundary list without replacing the values.

When to use this tool

Return indexes whose value differs from the previous supplied string, not CSS change hints or a value transform.

  • Prepare the supplied values fields for this operation.
  • Compare the complete example with the representation used by your own input before carrying the result into another step.

How to use the tool and how it works

  1. Enter values. Use the exact text syntax, units and index conventions explained below.
  2. Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
  3. Read result.changeIndexes. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.

Return each index greater than zero whose value is strictly unequal to the preceding value.1

Input fieldMeaning and representationAccepted input
valuesvalues.At most 128 strings, each at most 128 UTF-16 code units
Output fieldInterpretation
resultObject containing the named outputs below.
result.changeIndexesThe change indexes list in the ordering and representation described above.
json
{
  "input": {
    "values": [
      "a",
      "a",
      "b"
    ]
  },
  "output": {
    "result": {
      "changeIndexes": [
        2
      ]
    }
  }
}

Limitations and assumptions

  • The first element is never a change from an observed predecessor. Equality is exact; the tool does not group runs, normalize spelling or compare nonadjacent repetitions.
  • Every declared top-level field is required and unexpected fields are rejected. Numeric inputs must be finite; ordinary text fields are bounded to 8,192 UTF-16 code units, with tighter operation-specific limits where stated.
  • Ordinary string lists have at most 128 entries of at most 128 code units each; numeric lists and matrices have separate bounded size checks. Nonfinite results and excessively large serialized outputs are rejected.
  • Indexes are zero-based and spans have an exclusive end unless explicitly stated otherwise. A valid false, null or empty-list result is distinct from malformed input.

Alternative or Complementary methods

Use explicit source-index maps when rearranging data or planning missing-value fills. Keep row-major coordinates, cyclic indexes and one-based occurrence numbers distinct, and inspect null donor positions before copying values.

References

  1. Tool behavior and example: Adjacent Change Indexes — tool.io

Similar or alternative tools

  • Backward Fill Source Indexes

    Map backward fill source indexes from explicit binary knownness; missing sources are null and nearest-distance ties prefer the earlier index.

  • Forward Fill Source Indexes

    Map forward fill source indexes from explicit binary knownness; missing sources are null and nearest-distance ties prefer the earlier index.

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