gettype

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

The gettype function returns the runtime type of its argument as a string. Use this function when you need to determine the data type of fields, validate data structures, or debug type-related issues in your queries.

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, you use typeof to check types. APL’s gettype provides similar functionality with consistent type names.

Splunk example

| eval field_type=typeof(field_name)

ANSI SQL users

In ANSI SQL, type checking varies by database. APL’s gettype provides a standardized approach to runtime type detection.

SQL example

SELECT TYPEOF(field_name) AS field_type FROM logs;

Usage

Syntax

gettype(expression)

Parameters

Name	Type	Required	Description
expression	any	Yes	The expression whose type you want to determine.

Returns

Returns a string representing the runtime type: string, int, long, real, bool, datetime, timespan, dynamic, array, dictionary, or null.

Use case examples

Log analysis

Identify the data types of fields to ensure proper query operations and data validation.

Query

['sample-http-logs']
| extend status_type = gettype(status), 
         duration_type = gettype(req_duration_ms),
         time_type = gettype(_time)
| project status, status_type, req_duration_ms, duration_type, _time, time_type
| limit 10

Run in Playground

Output

status	status_type	req_duration_ms	duration_type	_time	time_type
200	string	145	long	2024-11-06T10:00:00Z	datetime
404	string	89	long	2024-11-06T10:01:00Z	datetime
500	string	234	long	2024-11-06T10:02:00Z	datetime

This query identifies the data types of key fields in HTTP logs, helping ensure that data is in the expected format for analysis and troubleshooting type-related query issues.

List of related functions

• isnull: Checks if a value is null. Use this to specifically test for null values rather than getting the type.
• isnotnull: Checks if a value is not null. Use this in filters when you need to exclude null values.
• parse_json: Parses JSON strings into dynamic types. Use this before gettype when working with JSON data.