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’).

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, string comparisons are case-insensitive by default. APL requires the explicit in~ operator for case-insensitive matching. Use in~ when you want to match values regardless of case.

Splunk example

index=web_logs | where method IN ("get", "post", "put")

['sample-http-logs']
| where method in~ ('get', 'post', 'put')

ANSI SQL users

In ANSI SQL, the IN operator’s case sensitivity depends on the database collation. APL’s in~ operator explicitly performs case-insensitive matching, similar to SQL databases with case-insensitive collation.

SQL example

SELECT * FROM sample_http_logs WHERE LOWER(method) IN ('get', 'post', 'put')

['sample-http-logs']
| where method in~ ('get', 'post', 'put')

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

Log analysis

Filter HTTP logs by method regardless of case.

Query

['sample-http-logs']
| where method in~ ('get', 'post')
| project _time, method, uri, status

Run in Playground

Output

_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.

OpenTelemetry traces

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, duration

Run in Playground

Output

_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 true if the value is not 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 within where clauses.
• =~: Use for single value case-insensitive equality checks. Use in~ when checking against multiple values.