toupper

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

The toupper function converts all characters in a string to uppercase. Use this function to normalize text for case-insensitive operations, standardize identifiers, or format strings for emphasis in output.

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 the upper function. APL’s toupper provides the same functionality.

Splunk example

| eval uppercase=upper(field)

['sample-http-logs']
| extend uppercase = toupper(field)

ANSI SQL users

In ANSI SQL, you use UPPER for uppercase conversion. APL’s toupper provides the same functionality.

SQL example

SELECT UPPER(field) AS uppercase FROM logs;

['sample-http-logs']
| extend uppercase = toupper(field)

Usage

Syntax

toupper(value)

Parameters

Name	Type	Required	Description
value	string	Yes	The input string to convert to uppercase.

Returns

Returns the input string with all characters converted to uppercase.

Use case examples

Log analysis

Standardize HTTP status codes and methods for consistent alerting and reporting.

Query

['sample-http-logs']
| extend normalized_method = toupper(method)
| extend alert_status = iff(status startswith '5', toupper(strcat('ERROR_', status)), status)
| summarize request_count = count() by normalized_method, alert_status
| sort by request_count desc
| limit 10

Run in Playground

Output

normalized_method	alert_status	request_count
GET	200	5432
POST	201	2341
GET	ERROR_500	234

This query normalizes HTTP methods to uppercase and creates emphasized error status codes for critical alerts.

OpenTelemetry traces

Create uppercase service identifiers for system monitoring and alerting.

Query

['otel-demo-traces']
| extend service_code = toupper(substring(['service.name'], 0, 3))
| summarize span_count = count(), avg_duration = avg(duration) by service_code
| sort by span_count desc
| limit 10

Run in Playground

Output

service_code	span_count	avg_duration
FRO	4532	125ms
CHE	3421	234ms
CAR	2987	89ms

This query creates three-letter uppercase service codes for compact monitoring displays and alerts.

List of related functions

• tolower: Converts strings to lowercase. Use this for the opposite transformation.
• totitle: Converts strings to title case. Use this for capitalized formatting.
• strcmp: Compares strings. Use toupper before strcmp for case-insensitive comparisons.
• strcat: Concatenates strings. Use this with toupper to build emphasized messages.