> ## Documentation Index
> Fetch the complete documentation index at: https://docs.m3ter.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Lookup Functions

Three Lookup functions are available for use in your Derived Field calculations:

* `Lookup.findNumber`
* `Lookup.findString`
* `Lookup.exists`

## `Lookup.findNumber`

`Lookup.findNumber()` is a multi-argument function which returns a number value and is of the generalized form:

> `Lookup.findNumber(<table_code>, <return_field>, <default_value>, <key1>, <key2>, ...)`

For example:

> `Lookup.findNumber("discount_vol_rates", "rate", 1, "country")`

* This will lookup the number value for the `rate` field in the published Table Revision of the  `discount_vol_rates` Lookup Table for the `country` keyed field.
* The `country` keyed field *must be present* in the measurement.
* If no match is found, then a default value of **1** will be used for the `rate`.

## `Lookup.findString`

`Lookup.findString()` is a multi-argument function which returns a string value and is of the generalized form:

> `Lookup.findString(<table_code>, <return_field>, <default_value>, <key1>, <key2>, ...)`

For example:

> `Lookup.findString("account_ops_status", "standing", "Pending", "ops_status")`

* This will lookup the string value for the `standing` field in the published Table Revision of the  `account_ops_status` Lookup Table for the `ops_status` keyed field.
* The `ops_status` keyed field *must be present* in the measurement.
* If no match is found, then a default value of **Pending** will be used for the `standing`.

## `Lookup.exists`

`Lookup.exists()` is a multi-argument function which returns true if found, false if not. It has the generalized form:

> `Lookup.exists(<table_code>, <key1> [, <key2>, ...])`

This Lookup function is typically used in conditional blocks and ternary expressions. For example:

> `Lookup.exists(<example_table_code>, <examplekey1> [, <examplekey2>, ...])`