MongoDB $exp Operator

MongoDB's aggregationframework provides a powerful set of tools for data manipulation and processing. One such tool is the $exp operator which allows users to perform exponential calculations within aggregation pipelines. In this article, We will learn about the MongoDB $exp Operator in detail.

MongoDB $exp Operator

• The $exp operator in MongoDB is used to raise the mathematical constant e (approximately equal to 2.718) to the power of a given number.
  
• It is commonly used in mathematical computations and can be included in aggregation pipelines to perform exponential calculations.

Syntax: 

{ $exp: <exponent> }

Here, the exponent is a valid expression until it resolves to a number. 

• If the entered value resolves to null, then this operator will return null.
• If the entered value resolves to NaN, then this operator will return NaN.
• If the entered value refers to a missing field, then this operator will return null.

Examples of MongoDB $exp

In the following examples, we are working with:

Database: GeeksforGeeks

Collection: example

Document: two documents that contain the details of the shapes in the form of field-value pairs.

Output:

Example 1: Using $exp Operator

In this example, we are going to find the exponent of the value of the side field.

db.example.aggregate([ {$match: {name: "Square"}},
... {$project: {result: {$exp: "$side"}}}])

Output:

Example 2: Using $exp Operator in the Embedded Document

In this example, we are going to find the exponent of the difference of the values of measurement.height and measurement.width fields.

db.example.aggregate([ {$match: {name: "Rectangle"}},
... {$project: {result: {$exp:
... {$subtract: ["$measurement.height", "$measurement.width"]}}}}])

Output:

Conclusion

The $exp operator in MongoDB is a useful tool for performing exponential calculations within aggregation pipelines. By raising e to a specified power, it facilitates complex mathematical computations in your MongoDB queries.