Run Length Record Value Window Count

Description

Count exact logical occurrences of one literal value in an explicit half-open window without expanding.

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.

Count exact logical occurrences of one literal value in an explicit half-open window without expanding.

When to use this tool

Use this tool to count exact logical occurrences of one literal value in an explicit half-open window without expanding.

How to use the tool and how it works

Enter runsJson, start, end, value 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.count, using the stated boundary, ordering, sign and absence conventions.

Slice the expanded half-open interval [start,end), retain runs with exact matching value and sum their lengths with exact integer arithmetic. Return count as decimal text.^[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.
value	Exact literal string value to select, count or find.	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.count	Exact matching expanded-observation count as decimal text.

json

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

Limitations and assumptions

Offsets count expanded observations, not run records. The interval must satisfy 0≤start≤end≤total.
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 Value Window Count — tool.io

Similar or alternative tools

Run Length Record Value First Offset
Run lengths are positive exact integer decimal strings with literal string values, never expanded; find the first logical offset of a literal value, retaining null when absent rather than using a sentinel position.
Run Length Record Value Map
Run lengths are positive exact integer decimal strings with literal string values, never expanded; map explicit literal values by a unique-key caller map and compact newly adjacent equal runs; mapping may deliberately merge values.