strcat_array

This page explains how to use the strcat_array function in APL.

The strcat_array function in Axiom Processing Language (APL) allows you to concatenate the elements of an array into a single string, with an optional delimiter separating each element. This function is useful when you need to transform a set of values into a readable or exportable format, such as combining multiple log entries, tracing IDs, or security alerts into a single output for further analysis or reporting.

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.

Splunk SPL users

In Splunk SPL, concatenation typically involves transforming fields into a string using the eval command with the + operator or mvjoin() for arrays. In APL, strcat_array simplifies array concatenation by natively supporting array input with a delimiter.

Splunk example

| eval concatenated=mvjoin(array_field, ", ")

ANSI SQL users

In ANSI SQL, concatenation involves functions like STRING_AGG() or manual string building using CONCAT(). APL’s strcat_array is similar to STRING_AGG(), but focuses on array input directly with a customizable delimiter.

SQL example

SELECT STRING_AGG(column_name, ', ') AS concatenated FROM table;

Usage

Syntax

strcat_array(array, delimiter)

Parameters

Parameter	Type	Description
array	dynamic	The array of values to concatenate.
delimiter	string	The string used to separate each element in the concatenated result. Optional. Defaults to an empty string if not specified.

Returns

A single concatenated string with the array’s elements separated by the specified delimiter.

Use case example

You can use strcat_array to combine HTTP methods and URLs for a quick summary of unique request paths.

Query

['sample-http-logs']
| take 50
| extend combined_requests = strcat_delim(' ', method, uri)
| summarize requests_list = make_list(combined_requests)
| extend paths = strcat_array(requests_list, ', ')

Run in Playground

Output

paths
GET /index, POST /submit, GET /about

This query summarizes unique HTTP method and URL combinations into a single, readable string.

List of related functions

• array_length: Returns the number of elements in an array.
• array_index_of: Finds the index of an element in an array.
• array_concat: Combines multiple arrays.