MongoDB $floor Operator

Posted in mongoDB Tutorial

Updated on Oct 31, 2024

By Mari Selvan

👁️ 22 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In MongoDB's aggregation framework, the $floor operator serves as a powerful tool for rounding down numerical values to the nearest integer or specified decimal place. This operator is invaluable for various data manipulation tasks, especially when dealing with numerical data that requires precision and consistency.

Let's delve into the details of how the $floor operator functions within MongoDB's aggregation pipelines.

💡 Syntax

The syntax for the $floor method is straightforward:

syntax.js

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{ $floor: <expression> }

$floor: This operator signifies that the subsequent operation will round down the numerical value.
<expression>: This represents the expression that evaluates to the numerical value to be rounded down.

📝 Example

⌨️ Input

Consider a collection named temperatures containing documents with fields location and temperature representing temperature data in various locations. Here are sample documents from the temperatures collection:

Input

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[
  { "_id": ObjectId("609c26812e9274a86871bc6a"), "location": "New York", "temperature": 23.5 },
  { "_id": ObjectId("609c26812e9274a86871bc6b"), "location": "Los Angeles", "temperature": 31.8 },
  { "_id": ObjectId("609c26812e9274a86871bc6c"), "location": "Chicago", "temperature": 17.2 }
]

🔄 Aggregation

Suppose we want to round down the temperature values to the nearest integer. Here's how you can achieve this using the $floor operator:

example.js

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db.temperatures.aggregate([
  {
    $project: {
      location: 1,
      roundedTemperature: { $floor: "$temperature" }
    }
  }
])

🧩 Explanation

$project: This stage reshapes documents by including or excluding fields. Here, we include the location field and create a new field roundedTemperature.
$floor: Rounds down the temperature field to the nearest integer.

When discussing how the above aggregation works:

For the first document, with "New York" as the location and a temperature of 23.5, the $floor operation rounds down 23.5 to 23, so the "roundedTemperature" becomes 23.
For the second document, with "Los Angeles" as the location and a temperature of 31.8, the $floor operation rounds down 31.8 to 31, so the "roundedTemperature" becomes 31.
For the third document, with "Chicago" as the location and a temperature of 17.2, the $floor operation rounds down 17.2 to 17, so the "roundedTemperature" becomes 17.

💻 Output

Now, let's take a look at the output generated by the aggregation pipeline:

Output

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{ "_id": ObjectId("609c26812e9274a86871bc6a"), "location": "New York", "roundedTemperature": 23 }
{ "_id": ObjectId("609c26812e9274a86871bc6b"), "location": "Los Angeles", "roundedTemperature": 31 }
{ "_id": ObjectId("609c26812e9274a86871bc6c"), "location": "Chicago", "roundedTemperature": 17 }

📚 Use Cases

Data Normalization:

The $floor operator is useful for normalizing numerical data, ensuring consistency and uniformity within datasets.
Statistical Analysis:

When performing statistical computations, rounding down temperature values can aid in summarizing data and identifying trends.
Visualization:

Rounded temperature values are often easier to interpret and visualize in graphs or charts, enhancing data presentation and understanding.

🎉 Conclusion

The $floor operator in MongoDB's aggregation framework provides a convenient solution for rounding down numerical values within aggregation pipelines. Whether you're normalizing data, performing statistical analysis, or enhancing data visualization, mastering the usage of $floor empowers you to efficiently manipulate numerical data and derive meaningful insights from your datasets.

With its intuitive syntax and versatile applications, the $floor operator proves to be an indispensable asset for handling numerical data effectively within MongoDB. Incorporate it into your aggregation pipelines to streamline data processing and unlock new dimensions of data analysis.