Use the array_reverse function in APL to reverse the order of elements in an array. This function is useful when you need to transform data where the sequence matters, such as reversing a list of events for chronological analysis or processing lists in descending order.

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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.

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Usage

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Syntax

array_reverse(array_expression)

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Parameters

  • array_expression: The array you want to reverse. This array must be of a dynamic type.

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Returns

Returns the input array with its elements in reverse order.

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Use case examples

Use array_reverse to inspect the sequence of actions in log entries, reversing the order to understand the initial steps of a user’s session.

Query

['sample-http-logs']
| summarize paths = make_list(uri) by id
| project id, reversed_paths = array_reverse(paths)

Run in Playground

Output

idreversed_paths
U1234[‘/home’, ‘/cart’, ‘/product’, ’/‘]
U5678[‘/login’, ‘/search’, ’/’]

This example identifies a user’s navigation sequence in reverse, showing their entry point into the system.

  • array_length: Returns the number of elements in an array.
  • array_shift_right: Shifts array elements to the right.
  • array_shift_left: Shifts array elements one position to the left, moving the first element to the last position.

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