in~
This page explains how to use the in~ operator in APL.
The in~ operator in APL filters records based on whether a value matches any element in a specified set using case-insensitive comparison. Use this operator to check if a field value equals one of several values regardless of letter case, which is more concise and efficient than chaining multiple equality checks with or. The in~ operator works with any scalar type, including strings, numbers, booleans, datetime values, and dynamic arrays.
Use the in~ operator when you need case-insensitive matching against multiple values, such as when filtering logs where the case of values might vary (for example, HTTP methods that could be 'GET', 'get', or 'Get').
Usage
Syntax
Expression in~ (Value1, Value2, ...)Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| Expression | scalar | Yes | The value to find in the given set, ignoring letter case. |
| Value | scalar or tabular | Yes | The values to compare against the expression. Specify individual scalar values, a dynamic array, or a subquery. When using a subquery with multiple columns, APL uses the first column. The operator supports up to 1,000,000 unique values in the set. |
Returns
Returns true if the expression value matches any value in the specified set (case-insensitive). Returns false otherwise.
Use case examples
Filter HTTP logs by method regardless of case.
Query
['sample-http-logs']
| where method in~ ('get', 'post')
| project _time, method, uri, statusOutput
| _time | method | uri | status |
|---|---|---|---|
| 2024-10-17 10:15:00 | GET | /api/users | 200 |
| 2024-10-17 10:16:30 | Post | /api/data | 201 |
| 2024-10-17 10:17:45 | get | /api/items | 200 |
This query filters the HTTP logs to return requests with GET or POST methods, regardless of how the method is capitalized in the data.
Identify traces by span kind regardless of case variations.
Query
['otel-demo-traces']
| where kind in~ ('server', 'client')
| project _time, trace_id, ['service.name'], kind, durationOutput
| _time | trace_id | service.name | kind | duration |
|---|---|---|---|---|
| 2024-10-17 11:00:00 | abc123 | frontend | Server | 45ms |
| 2024-10-17 11:00:05 | def456 | checkout | CLIENT | 120ms |
| 2024-10-17 11:00:10 | ghi789 | cart | server | 30ms |
This query filters traces to show spans with server or client kind, regardless of case, helping you analyze external-facing operations.
Performance considerations
When two operators perform the same task, use the case-sensitive one (in) for better performance. Use in~ only when case-insensitive matching is necessary.
Use with dynamic arrays
When you pass a dynamic array with nested arrays, APL flattens them into a single list. For instance, x in~ (dynamic(['a', ['b', 'c']])) is equivalent to x in~ ('a', 'b', 'c').
let methods = dynamic(['get', 'post']);
['sample-http-logs']
| where method in~ (methods)List of related operators
- in: Use for case-sensitive matching to include values. Better performance than
in~. - !in: Use for case-sensitive exclusion. Returns
trueif the value isn't in the set. - !in~: Use for case-insensitive exclusion. Excludes values regardless of case.
- where: Use to filter rows based on conditions. The
in~operator is commonly used withinwhereclauses. - =~: Use for single value case-insensitive equality checks. Use
in~when checking against multiple values.