array_index_of
This page explains how to use the array_index_of function in APL.
The array_index_of function in APL returns the zero-based index of the first occurrence of a specified value within an array. If the value isn’t found, the function returns -1. Use this function when you need to identify the position of a specific item within an array, such as finding the location of an error code in a sequence of logs or pinpointing a particular value within telemetry data arrays.
For users of other query languages
If you come from other query languages, this section explains how to adjust your existing queries to achieve the same results in APL.
Usage
Syntax
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| array | array | Yes | Input array to search. |
| lookup_value | scalar | Yes | Scalar value to search for in the array. Accepted data types: long, integer, double, datetime, timespan, or string. |
| start_index | number | No | The index where to start the search. A negative value offsets the starting search value from the end of the array by abs(start_index) steps. |
| length | number | No | Number of values to examine. A value of -1 means unlimited length. |
| occurrence | number | No | The number of the occurrence. By default 1. |
Returns
array_index_of returns the zero-based index of the first occurrence of the specified lookup_value in array. If lookup_value doesn’t exist in the array, it returns -1.
Use case examples
You can use array_index_of to find the position of a specific HTTP status code within an array of codes in your log analysis.
Query
Output
| status_array | index_500 |
|---|---|
| [“200”, “404”, “500”] | 2 |
This query creates an array of status codes and identifies the position of the first occurrence of the 500 status.
You can use array_index_of to find the position of a specific HTTP status code within an array of codes in your log analysis.
Query
Output
| status_array | index_500 |
|---|---|
| [“200”, “404”, “500”] | 2 |
This query creates an array of status codes and identifies the position of the first occurrence of the 500 status.
In OpenTelemetry traces, you can find the position of a specific service.name within an array of service names to detect when a particular service appears.
Query
Output
| service_array | frontend_index |
|---|---|
| [“frontend”, “cartservice”] | 0 |
This query collects the array of services and determines where the frontend service first appears.
When working with security logs, array_index_of can help identify the index of a particular error or status code, such as 500, within an array of status codes.
Query
Output
| status_array | index_500 |
|---|---|
| [“200”, “404”, “500”] | 2 |
This query helps identify at what index the 500 status code appears.
List of related functions
- array_concat: Combines multiple arrays.
- array_rotate_right: Rotates array elements to the right by a specified number of positions.
- array_rotate_left: Rotates elements of an array to the left.