$ln Operator - (MongoDB Misc)

The $ln operator is a mathematical operator available in MongoDB. It returns the natural logarithm of a number.

Syntax

The basic syntax of theln operator is as follows:

{ $ln: <number> }

The <number> is the value for which you want to get the natural logarithm.

Example

Let's consider the following collection of documents in a MongoDB database:

{
   "_id": 1,
   "value": 100
},
{
   "_id": 2,
   "value": 500
},
{
   "_id": 3,
   "value": 2000
}

In order to find the natural logarithm of the value of the value field for each document in this collection, you can execute the following aggregation query in the MongoDB shell:

db.collection.aggregate([
   { $project: { ln_value: { $ln: "$value" } } }
])

This query uses the $project operator to add a new field to each document in the collection called ln_value representing the natural logarithm of the value in the value field.

Output

The output of the above query will be:

{ "_id": 1, "ln_value": 4.605170185988092 }
{ "_id": 2, "ln_value": 6.214608098422191 }
{ "_id": 3, "ln_value": 7.600902459542082 }

Explanation

The natural logarithm of a number is the logarithm to the base e, where e is approximately equal to 2.71828. The $ln operator takes a number as input and returns the natural logarithm of that number.

Use

The $ln operator can be used in aggregation queries to perform mathematical operations on the values in a MongoDB collection. It can be useful when working with complex mathematical calculations.

Important Points- The $ln operator is a mathematical operator in MongoDB that returns the natural logarithm of a number.

• The natural logarithm of a number is the logarithm to the base e.
• The $ln operator can be used in aggregation queries to perform mathematical calculations.

Summary

In this page, we discussed the $ln operator which is a mathematical operator available in MongoDB. We covered its syntax, example, output, explanation, use, and important points. Use of the $ln operator can be helpful when carrying out complex mathematical calculations in MongoDB.