Alternating Sign Run Segmenter
Segment consecutive strictly alternating nonzero signs; zeros and equal adjacent signs break runs.
Description
Segment consecutive strictly alternating nonzero signs; zeros and equal adjacent signs break runs.
Alternating-sign segments identify stretches whose nonzero values switch sign at every step. Zero interrupts that pattern rather than acting as either sign.
When to use this tool
Segment consecutive strictly alternating nonzero signs; zeros and equal adjacent signs break runs.
- 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
- Enter values. Use the exact text syntax, units and index conventions explained below.
- Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
- Read result.segments. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Scan adjacent numeric values, ending a half-open segment when either side is zero or their signs agree. Emit the final segment and retain singleton segments.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| values | values. | List of finite numbers; bounded by the operation |
| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.segments | The segments list in the ordering and representation described above. |
{
"input": {
"values": [
1,
-1,
1,
2,
-2
]
},
"output": {
"result": {
"segments": [
{
"start": 0,
"end": 3
},
{
"start": 3,
"end": 5
}
]
}
}
}Limitations and assumptions
- Zeros become singleton segments when isolated by these boundaries. Magnitudes and strict monotonicity are irrelevant; the tool does not find every overlapping alternating subsequence.
- 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
Similar or alternative tools
- Monotonic Run Segmenter
Segment maximal weak-monotonic runs, sharing turning-point samples; flat steps retain the active direction and fully flat runs have direction zero.
- Equal Value Run Boundary Indexes
Return half-open equal-value run boundaries, including empty input; equality is exact supplied-string equality.