In MongoDB, the $log aggregation pipeline operator calculates the log of a number in the specified base and returns the result as a double.
operators
MongoDB $indexOfCP
In MongoDB, the $indexOfCP aggregation pipeline operator searches a string for an occurrence of a substring and returns the UTF code point index of the first occurrence.
The UTF code point index is zero-based (i.e. it starts at 0).
MongoDB $indexOfBytes
In MongoDB, the $indexOfBytes aggregation pipeline operator searches a string for an occurrence of a substring and returns the UTF-8 byte index of the first occurrence.
The UTF byte index is zero-based (i.e. it starts at 0).
MongoDB $indexOfArray
In MongoDB, the $indexOfArray aggregation pipeline operator searches an array for an occurrence of a specified value and returns the array index of the first occurrence.
MongoDB $trunc
In MongoDB, the $trunc aggregation pipeline operator truncates a number to a whole integer or to a specified decimal place.
You have the option of specifying how many decimal places for which to truncate the number. To do this, pass a second argument. The first argument is the number to truncate, and the second (optional) argument is the number of decimal places to truncate it to.
Omitting the second argument truncates all digits to the right of the decimal and returns the whole integer value.
MongoDB $or Aggregation Pipeline Operator
In MongoDB, the $or aggregation pipeline operator evaluates one or more expressions and returns true if any evaluate to true. Otherwise it returns false.
MongoDB $and Aggregation Pipeline Operator
In MongoDB, the $and aggregation pipeline operator evaluates one or more expressions and returns true if they all evaluate to true, or if its invoked with no arguments. Otherwise it returns false.
MongoDB $arrayToObject
In MongoDB, the $arrayToObject aggregation pipeline operator converts an array to a document.
MongoDB $objectToArray
In MongoDB, the $objectToArray aggregation pipeline operator converts a document to an array.
MongoDB $not Aggregation Pipeline Operator
In MongoDB, the $not aggregation pipeline operator evaluates a boolean and returns the opposite boolean value.
In other words, when the boolean evaluates to true, the $not operator returns false. And when the boolean evaluates to false, the $not operator returns true.