$arrayElemAt
Reference group: Array aggregation expressions
What it does
Returns the element at an index; negative indexes count from the end.
Syntax
{$arrayElemAt: [array, index]}
Use case
Select a boundary element from an ordered array.
$arrayElemAt: practical example
{ $project: { latest: { $arrayElemAt: ["$events", -1] } } }💡 Explanation
Returns the element at an index; negative indexes count from the end.
When to use it
Select a boundary element from an ordered array.
Key Takeaways
- Returns the element at an index; negative indexes count from the end.
- Typical use: Select a boundary element from an ordered array.