Run Length Record Range Slice

Description

Slice an exact half-open logical interval without expansion, preserving interior source-run boundaries.

Run-length records represent repeated observations without expanding them. Each record pairs a literal string value with a positive exact integer length; neighboring equal values can be valid but noncompact. Expanded offsets count observations rather than run records, and half-open ranges include their start while excluding their end.

Slice an exact half-open logical interval without expansion, preserving interior source-run boundaries.

When to use this tool

Use this tool to slice an exact half-open logical interval without expansion, preserving interior source-run boundaries.

How to use the tool and how it works

Enter runsJson, start, end using the definitions below. Serialize JSON text fields in the decoded shape shown below.
Run the operation. Resolve input-format errors before interpreting an output.
Read result.runs, using the stated boundary, ordering, sign and absence conventions.

Compute cumulative exact offsets and intersect every run with [start,end). Return positive overlap pieces as run records in original order without merging equal neighboring pieces.^[1]

Input field	Meaning and units	Accepted input
runsJson	JSON array of {value,length} records: literal string value and positive exact decimal-string length.	Text, at most 8,192 UTF-16 code units; narrower grammar/range rules also apply.
start	Inclusive expanded-observation offset as nonnegative exact decimal text.	Text, at most 8,192 UTF-16 code units; narrower grammar/range rules also apply.
end	Exclusive expanded-observation offset as exact decimal text, at least start and no greater than total.	Text, at most 8,192 UTF-16 code units; narrower grammar/range rules also apply.

These decoded structures show the examples inside JSON text fields. Supply their serialized JSON strings as input.

json

{
  "runsJson": [
    {
      "value": "a",
      "length": "3"
    },
    {
      "value": "a",
      "length": "2"
    },
    {
      "value": "b",
      "length": "4"
    }
  ]
}

Output field	Interpretation
result	Object containing the fields below.
result.runs	Resulting {value,length} records, with exact positive decimal lengths and the stated compaction policy.

json

{
  "input": {
    "runsJson": "[{\"value\": \"a\", \"length\": \"3\"}, {\"value\": \"a\", \"length\": \"2\"}, {\"value\": \"b\", \"length\": \"4\"}]",
    "start": "2",
    "end": "7"
  },
  "output": {
    "result": {
      "runs": [
        {
          "value": "a",
          "length": "1"
        },
        {
          "value": "a",
          "length": "2"
        },
        {
          "value": "b",
          "length": "2"
        }
      ]
    }
  }
}

Limitations and assumptions

The interval must be within the expanded total; slicing preserves source run boundaries rather than producing a canonical compact form.
Run records contain string value and positive length as exact decimal integer text. Lengths and offset inputs support up to 256 decimal digits before operation-specific checks; results use decimal text and do not expand the repeated observations.
Every declared outer field is required and unknown outer fields are rejected. Strings and JSON text have size limits, lists are bounded to 128 entries, and JSON nesting/node counts are bounded. Tighter operation-specific bounds stated above take precedence.
Ordinary numeric outputs must be finite and within safe-integer magnitude. Exact large lengths/counts use decimal strings. Original record indexes and code-unit positions are zero-based; span ends are exclusive unless stated otherwise.

Alternative or Complementary methods

Use compaction for a canonical adjacent-run layout and boundary-aware operations when provenance matters. Retain exact decimal lengths rather than converting long totals to floating-point numbers.

References

Tool behavior and example: Run Length Record Range Slice — tool.io

Similar or alternative tools

Run Length Record Range Splice
Run lengths are positive exact integer decimal strings with literal string values, never expanded; splice a bounded exact half-open range with encoded replacement records and compact the resulting join boundaries.
Run Length Record Adjacent Compaction
Run lengths are positive exact integer decimal strings with literal string values, never expanded; compact adjacent exactly equal values by summing exact lengths, not global deduplication.