Details
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New Feature
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Status: Closed
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Minor - P4
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Resolution: Fixed
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None
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Fully Compatible
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Query 11 (03/14/16)
Description
Syntax
{$reverseArray: <expression which evaluates to an array>}
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Examples
Input
{_id: 0, a: [1, 2, 3]}
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Pipeline
db.coll.aggregate([{
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$project: {
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reversed: {$reverseArray: "$a"} |
}
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}])
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Output
{_id: 0, reversed: [3, 2, 1]}
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Additional Notes
- Can be used in combination with $reduce to yield the equivalent of a $foldR.
- Returns null if input is nullish.
- Errors if input is not an array or nullish.
Original Description
Aggregation should support an $reverseArray expression, which accepts as input an expression that evaluates to an array, and outputs the reversed version of the array. Throws an error if the input is not an array or nullish.
Attachments
Issue Links
- is depended on by
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CSHARP-1608 Aggregation should have a $reverseArray expression.
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- Closed
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- is documented by
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DOCS-8483 Document reverseArray
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- Closed
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- is related to
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DRIVERS-297 Aggregation Framework Support for 3.4
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- Closed
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