Array Aggregation Operators


For details on specific operator, including syntax and examples, click on the specific operator to go to its reference page.

Name Description
$arrayElemAt Returns the element at the specified array index.
$concatArrays Concatenates arrays to return the concatenated array.
$filter Selects a subset of the array to return an array with only the elements that match the filter condition.
$isArray Determines if the operand is an array. Returns a boolean.
$size Returns the number of elements in the array. Accepts a single expression as argument.
$slice Returns a subset of an array.