Table/Lookup Operators

Advanced table operations for data lookups, indexing, and queries.

`VALUEAT` - Get Value from Table

Retrieves a value from a table (array of objects) by row index and optional column name.

Syntax

{"VALUEAT": [table, row_index]}
{"VALUEAT": [table, row_index, column_name]}

Parameters

table (array): Array of objects
row_index (number): Row index (0-based)
column_name (string, optional): Column/field name

Return Type

Any - Entire row object or specific column value, null if not found

Examples

Get entire row:

// Data: {"table": [
//   {"name": "Alice", "age": 30},
//   {"name": "Bob", "age": 25},
//   {"name": "Charlie", "age": 35}
// ]}
{"VALUEAT": [{"var": "table"}, 1]}
// → {"name": "Bob", "age": 25}

Get specific column:

{"VALUEAT": [{"var": "table"}, 1, "name"]}  // → "Bob"
{"VALUEAT": [{"var": "table"}, 2, "age"]}   // → 35

Out of bounds:

{"VALUEAT": [{"var": "table"}, -1]}   // → null
{"VALUEAT": [{"var": "table"}, 999]}  // → null

Dynamic index:

{"VALUEAT": [
  {"var": "rates"},
  {"INDEXAT": [{"var": "age"}, {"var": "rates"}, "minAge"]},
  "rate"
]}

With FOR loop:

{"FOR": [
  0,
  {"-": [{"length": {"var": "table"}}, 1]},
  {"VALUEAT": [{"var": "table"}, {"var": "$iteration"}, "value"]}
]}

`MAXAT` - Get Last Row Value

Returns a column value from the last row of a table.

Syntax

{"MAXAT": [table, column_name]}

Parameters

table (array): Array of objects
column_name (string): Field name to extract

Return Type

Any - Value from last row’s column, null if table is empty

Examples

Get last value:

// Data: {"table": [
//   {"name": "Alice", "score": 85},
//   {"name": "Bob", "score": 92},
//   {"name": "Charlie", "score": 78}
// ]}
{"MAXAT": [{"var": "table"}, "score"]}  // → 78 (Charlie's score)

Assumes sorted data:

// If table is sorted by age ascending, get maximum age
{"MAXAT": [{"var": "sortedByAge"}, "age"]}

Get latest entry:

{"MAXAT": [{"var": "history"}, "timestamp"]}

`INDEXAT` - Find Index

Finds the index of an element in a table by field value.

Syntax

{"INDEXAT": [lookup_value, table, field]}
{"INDEXAT": [lookup_value, table, field, range]}

Parameters

lookup_value (any): Value to find
table (array): Array of objects to search
field (string): Field name to compare
range (boolean, optional): If true, finds first where field <= value

Return Type

Number - Index (0-based) of match, or -1 if not found

Examples

Exact match:

// Data: {"table": [
//   {"id": 100, "name": "Alice"},
//   {"id": 200, "name": "Bob"},
//   {"id": 300, "name": "Charlie"}
// ]}
{"INDEXAT": [200, {"var": "table"}, "id"]}  // → 1

Not found:

{"INDEXAT": [999, {"var": "table"}, "id"]}  // → -1

Range search (first where field <= value):

{"INDEXAT": [250, {"var": "table"}, "id", true]}  // → 0 (first id <= 250)

Lookup and retrieve:

{"VALUEAT": [
  {"var": "table"},
  {"INDEXAT": [{"var": "searchId"}, {"var": "table"}, "id"]},
  "name"
]}

`MATCH` - Match Row by Conditions

Finds the index of first row matching all specified field-value pairs.

Syntax

{"MATCH": [table, value1, field1, value2, field2, ...]}

Parameters

table (array): Array of objects
value, field (pairs): Value-field pairs to match (all must match)

Return Type

Number - Index of first matching row, or -1 if not found

Examples

Single condition:

// Data: {"table": [
//   {"name": "Alice", "age": 30, "city": "NYC"},
//   {"name": "Bob", "age": 25, "city": "LA"},
//   {"name": "Charlie", "age": 35, "city": "NYC"}
// ]}
{"MATCH": [{"var": "table"}, "Alice", "name"]}  // → 0

Multiple conditions (AND):

{"MATCH": [{"var": "table"}, "Alice", "name", "NYC", "city"]}
// → 0 (Alice in NYC)

{"MATCH": [{"var": "table"}, "Bob", "name", "NYC", "city"]}
// → -1 (Bob not in NYC)

Not found:

{"MATCH": [{"var": "table"}, "David", "name"]}  // → -1

Retrieve matched row:

{"VALUEAT": [
  {"var": "table"},
  {"MATCH": [{"var": "table"}, "Alice", "name"]}
]}

`MATCHRANGE` - Match Value in Range

Finds the index of first row where value falls between min and max fields.

Syntax

{"MATCHRANGE": [table, min_field, max_field, value]}

Parameters

table (array): Array of objects with range fields
min_field (string): Field name for minimum value
max_field (string): Field name for maximum value
value (number): Value to check

Return Type

Number - Index of first row where min <= value <= max, or -1 if not found

Examples

Rate table lookup:

// Data: {"rates": [
//   {"min_age": 0, "max_age": 25, "rate": 0.05},
//   {"min_age": 26, "max_age": 40, "rate": 0.07},
//   {"min_age": 41, "max_age": 60, "rate": 0.09}
// ]}

{"MATCHRANGE": [{"var": "rates"}, "min_age", "max_age", 30]}
// → 1 (30 falls in 26-40 range)

{"MATCHRANGE": [{"var": "rates"}, "min_age", "max_age", 50]}
// → 2 (50 falls in 41-60 range)

Get rate for age:

{"VALUEAT": [
  {"var": "rates"},
  {"MATCHRANGE": [{"var": "rates"}, "min_age", "max_age", {"var": "age"}]},
  "rate"
]}

Tax bracket:

{"MATCHRANGE": [
  {"var": "taxBrackets"},
  "min_income",
  "max_income",
  {"var": "income"}
]}

`CHOOSE` - Choose Random/First Match

Finds the index of any (typically first) row matching the condition.

Syntax

{"CHOOSE": [table, value, field, ...]}

Parameters

table (array): Array of objects
value, field (pairs): Condition pairs

Return Type

Number - Index of a matching row, or -1 if not found

Examples

Find any match:

// Data: {"products": [
//   {"name": "Widget", "category": "A", "price": 10},
//   {"name": "Gadget", "category": "B", "price": 20},
//   {"name": "Tool", "category": "A", "price": 15}
// ]}

{"CHOOSE": [{"var": "products"}, "A", "category"]}
// → 0 or 2 (any item in category A)

Get matched product:

{"VALUEAT": [
  {"var": "products"},
  {"CHOOSE": [{"var": "products"}, "A", "category"]},
  "name"
]}

`FINDINDEX` - Find Index with Complex Conditions

Finds the index of first row matching complex conditions with ergonomic syntax.

Syntax

{"FINDINDEX": [table, condition1, condition2, ...]}

Conditions Format

String literals - Treated as field name checks (truthy):

"fieldName"  // row.fieldName is truthy

Array format - Comparison triplets [op, value, field]:

[">", 15, "age"]  // row.age > 15
["==", "active", "status"]  // row.status == "active"

Object format - Standard logic expressions:

{">": [{"var": "age"}, 18]}

Return Type

Number - Index of first matching row, or -1 if not found

Examples

Simple field check:

// Data: {"items": [
//   {"value": 10, "active": false},
//   {"value": 20, "active": true},
//   {"value": 30, "active": true}
// ]}

{"FINDINDEX": [{"var": "items"}, "active"]}
// → 1 (first active item)

With comparison:

{"FINDINDEX": [
  {"var": "items"},
  [">", 15, "value"]
]}
// → 1 (first item where value > 15)

Multiple conditions (AND):

{"FINDINDEX": [
  {"var": "items"},
  "active",
  [">", 15, "value"]
]}
// → 2 (first item where active=true AND value > 15)

Complex logic:

{"FINDINDEX": [
  {"var": "users"},
  {">": [{"var": "score"}, 70]},
  {"==": [{"var": "status"}, "verified"]}
]}

Complex Examples

Lookup with Fallback

{"ifnull": [
  {"VALUEAT": [
    {"var": "table"},
    {"INDEXAT": [{"var": "key"}, {"var": "table"}, "id"]},
    "value"
  ]},
  "default"
]}

Multi-Table Lookup

{"VALUEAT": [
  {"var": "rates"},
  {"MATCH": [
    {"var": "rates"},
    {"var": "category"},
    "category",
    {"var": "type"},
    "type"
  ]},
  "multiplier"
]}

Range-Based Calculation

{"*": [
  {"var": "amount"},
  {"VALUEAT": [
    {"var": "brackets"},
    {"MATCHRANGE": [
      {"var": "brackets"},
      "min",
      "max",
      {"var": "income"}
    ]},
    "rate"
  ]}
]}

Find and Update Pattern

{
  "let": {
    "index": {"FINDINDEX": [{"var": "items"}, "selected"]},
    "found": {">": [{"var": "index"}, -1]}
  },
  "in": {
    "if": [
      {"var": "found"},
      {"VALUEAT": [{"var": "items"}, {"var": "index"}]},
      null
    ]
  }
}

Nested Table Lookup

{"VALUEAT": [
  {"VALUEAT": [
    {"var": "masterTable"},
    {"INDEXAT": [{"var": "masterId"}, {"var": "masterTable"}, "id"]},
    "detailTable"
  ]},
  {"INDEXAT": [{"var": "detailId"}, detailTable, "id"]},
  "value"
]}

Age-Based Rate with Range

{"VALUEAT": [
  {"$ref": "$params.mortality_table"},
  {"MATCHRANGE": [
    {"$ref": "$params.mortality_table"},
    "min_age",
    "max_age",
    {"var": "current_age"}
  ]},
  "rate"
]}

Comparison Table

Operator	Use Case	Match Type	Return
VALUEAT	Direct access by index	Index-based	Value or row
MAXAT	Get last row value	Last element	Column value
INDEXAT	Find by exact match	Exact or range	Index
MATCH	Find by multiple fields	Exact (AND)	Index
MATCHRANGE	Find by value in range	Range	Index
CHOOSE	Find any match	Exact	Index
FINDINDEX	Complex conditions	Custom logic	Index

Best Practices

Combine operators for lookups

{"VALUEAT": [table, {"INDEXAT": [value, table, field]}, column]}

Check for not found (-1)

{"if": [
  {">": [{"INDEXAT": [value, table, field]}, -1]},
  foundLogic,
  notFoundLogic
]}

Use MATCHRANGE for bracketed data

{"MATCHRANGE": [brackets, "min", "max", value]}

Cache lookups when used multiple times

// Store index result if used repeatedly

Validate table structure before lookup

{"if": [
  {">": [{"length": {"var": "table"}}, 0]},
  lookup,
  default
]}

Common Patterns

Progressive Lookup

{"ifnull": [
  {"VALUEAT": [primary, index, field]},
  {"ifnull": [
    {"VALUEAT": [secondary, index, field]},
    default
  ]}
]}

Tiered Rate Table

{"VALUEAT": [
  {"var": "rateTables"},
  {"MATCHRANGE": [
    {"var": "rateTables"},
    "minValue",
    "maxValue",
    {"var": "input"}
  ]},
  "rate"
]}

Conditional Table Selection

{"VALUEAT": [
  {"if": [
    {"var": "usePremium"},
    {"var": "premiumRates"},
    {"var": "standardRates"}
  ]},
  {"INDEXAT": [{"var": "age"}, table, "minAge"]},
  "rate"
]}

Array Operators - filter, map, find alternatives
Comparison Operators - Build conditions
Logical Operators - Combine conditions

Performance Notes

Linear search for MATCH, FINDINDEX, CHOOSE
Indexed access for VALUEAT is O(1)
Early termination on first match
Table caching recommended for repeated lookups

Table/Lookup Operators

VALUEAT - Get Value from Table

Syntax

Parameters

Return Type

Examples

MAXAT - Get Last Row Value

Syntax

Parameters

Return Type

Examples

INDEXAT - Find Index

Syntax

Parameters

Return Type

Examples

MATCH - Match Row by Conditions

Syntax

Parameters

Return Type

Examples

MATCHRANGE - Match Value in Range

Syntax

Parameters

Return Type

Examples

CHOOSE - Choose Random/First Match

Syntax

Parameters

Return Type

Examples

FINDINDEX - Find Index with Complex Conditions

Syntax

Conditions Format

Return Type

Examples

Complex Examples

Lookup with Fallback

Multi-Table Lookup

Range-Based Calculation

Find and Update Pattern

Nested Table Lookup

Age-Based Rate with Range

Comparison Table

Best Practices

Common Patterns

Progressive Lookup

Tiered Rate Table

Conditional Table Selection

Related Operators

Performance Notes

`VALUEAT` - Get Value from Table

`MAXAT` - Get Last Row Value

`INDEXAT` - Find Index

`MATCH` - Match Row by Conditions

`MATCHRANGE` - Match Value in Range

`CHOOSE` - Choose Random/First Match

`FINDINDEX` - Find Index with Complex Conditions