Multi Key Order Witness

Compare two numeric multi-key tuples with per-key ascending/descending directions, exposing the first decisive key rather than coercing ties.

Description

Compare two numeric multi-key tuples with per-key ascending/descending directions, exposing the first decisive key rather than coercing ties.

A multi-key comparison stops at its first differing key, with per-key ascending or descending direction.

When to use this tool

Compare two numeric multi-key tuples with per-key ascending/descending directions, exposing the first decisive key rather than coercing ties.

  • Prepare the supplied left, right, directions 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 left, right, directions. 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.decisiveKey, result.order. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.

Require equal list lengths and directions each +1 or -1. Return the first unequal zero-based key index and the sign of left minus right multiplied by its direction. Equal tuples give null and zero.1

Input fieldMeaning and representationAccepted input
leftleft.List of finite numbers; at most 128 entries
rightright.List of finite numbers; at most 128 entries
directionsdirections.List of finite numbers; at most 128 entries
Output fieldInterpretation
resultObject containing the named outputs below.
result.decisiveKeyThe decisive key value under the stated formula or text convention.
result.orderComparison result under the exact convention above; -1 means left before right, 0 equal, +1 after.
json
{
  "input": {
    "left": [
      1,
      3
    ],
    "right": [
      1,
      2
    ],
    "directions": [
      1,
      -1
    ]
  },
  "output": {
    "result": {
      "decisiveKey": 1,
      "order": -1
    }
  }
}

Limitations and assumptions

  • No key extraction, locale collation or tolerance is applied. Large finite subtraction can overflow to infinity internally, but its sign is still used.
  • All declared input fields are required and unexpected top-level fields are rejected. Numbers must be finite; lists are limited to 128 entries and ordinary text fields to 8,192 UTF-16 code units, with tighter limits where stated.
  • JSON text inputs must parse within bounded nesting and size limits. Numeric outputs outside the safe finite range are rejected; large exact integer results use decimal strings. Indexes and half-open spans are zero-based unless a rank is explicitly described as one-based.

Alternative or Complementary methods

Choose the tie policy and whether you need values, original indexes, sorted positions or one-based ranks. Use a complete sort verifier when a local stability or adjacent-comparison check is insufficient.

References

  1. Tool behavior and example: Multi Key Order Witness — tool.io

Similar or alternative tools

  • Lexicographic Tuple Order Check

    Check finite numeric tuples in lexicographic order, with shorter matching prefixes before longer tuples and explicit adjacent failure witnesses.

  • Rank Order Agreement Pairs

    Classify numeric rank-order pair agreement and disagreement while retaining all pairs tied in either observation; not a normalized correlation coefficient.

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