array_select_dict

The array_select_dict function in APL allows you to retrieve a dictionary from an array of dictionaries based on a specified key-value pair. This function is useful when you need to filter arrays and extract specific dictionaries for further processing. If no match exists, it returns null. Non-dictionary values in the input array are ignored.

​

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

array_select_dict(array, key, value)

​

Parameters

​

Returns

The function returns the first dictionary in the array that matches the specified key-value pair. If no match exists, it returns null. Non-dictionary elements in the array are ignored.

​

Use case example

This example demonstrates how to use array_select_dict to extract a dictionary where the key service.name has the value frontend.

Query

['sample-http-logs']
| extend array = dynamic([{"service.name": "frontend", "status_code": "200"}, {"service.name": "backend", "status_code": "500"}])
| project selected = array_select_dict(array, "service.name", "frontend")

Run in Playground

Output

{"service.name": "frontend", "status_code": "200"}

This query selects the first dictionary in the array where service.name equals frontend and returns it.

​

List of related functions

• array_index_of: Finds the index of an element in an array.
• array_concat: Combines multiple arrays.
• array_rotate_right: Rotates array elements to the right by a specified number of positions.