trim_end_regex
This page explains how to use the trim_end_regex function in APL.
The trim_end_regex function removes all trailing matches of a regular expression pattern from a string. Use this function to remove complex patterns from string endings, clean structured log suffixes, or normalize data with pattern-based trimming.
Usage
Syntax
trim_end_regex(regex, text)Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| regex | string | Yes | The regular expression pattern to remove from the end. |
| text | string | Yes | The source string to trim. |
Returns
Returns the source string with trailing regex matches removed.
Use case examples
Remove trailing numeric suffixes or version numbers from URIs.
Query
['sample-http-logs']
| extend cleaned_uri = trim_end_regex('[0-9]+$', uri)
| summarize request_count = count() by cleaned_uri, method
| sort by request_count desc
| limit 10Output
| cleaned_uri | method | request_count |
|---|---|---|
| /api/users/ | GET | 2341 |
| /api/orders/ | POST | 1987 |
This query removes trailing numeric IDs from URIs, allowing aggregation by endpoint type rather than individual resources.
Remove version suffixes from service names using regex patterns.
Query
['otel-demo-traces']
| extend cleaned_service = trim_end_regex('-v[0-9]+[.][0-9]+$', ['service.name'])
| summarize span_count = count() by cleaned_service
| sort by span_count desc
| limit 10Output
| cleaned_service | span_count |
|---|---|
| frontend | 4532 |
| checkout | 3421 |
| cart | 2987 |
This query removes version number suffixes like '-v1.0' or '-v2.3' from service names, enabling cross-version analysis.
Remove trailing hexadecimal session tokens or identifiers from URIs.
Query
['sample-http-logs']
| extend cleaned_uri = trim_end_regex('[a-f0-9]{8,}$', uri)
| summarize attempts = count() by cleaned_uri, status
| sort by attempts desc
| limit 10Output
| cleaned_uri | status | failed_attempts |
|---|---|---|
| /api/session/ | 401 | 234 |
| /admin/token/ | 403 | 156 |
This query removes trailing hexadecimal tokens from URIs, helping identify which endpoints are targeted in authentication attempts without session-specific noise.
List of related functions
- trim_end: Removes trailing characters. Use this for simple character-based trimming without regex.
- trim_regex: Removes both leading and trailing regex matches. Use this for bidirectional pattern trimming.
- replace_regex: Replaces regex matches. Use this when you need to replace patterns rather than just remove trailing ones.
- trim_start_regex: Removes leading regex matches. Use this to trim patterns from the beginning.