Table of contents
1.
Introduction
2.
Why This Function is Used
3.
Syntax, Parameter and Return Value
3.1.
Syntax: 
3.2.
Parameters:
3.3.
Return Value: 
4.
Examples 
4.1.
Rounding Down to Nearest Integer:
4.2.
JavaScript
4.3.
Rounding Down with Precision:
4.4.
JavaScript
4.5.
Financial Calculations:
4.6.
JavaScript
4.7.
Using in Array Operations:
4.8.
JavaScript
5.
Frequently Asked Questions
5.1.
How does _.floor() differ from JavaScript's Math.floor()?
5.2.
Can _.floor() handle negative numbers?
5.3.
Is _.floor() suitable for all numerical rounding needs?
6.
Conclusion
Last Updated: Mar 27, 2024
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Lodash _.floor() Method

Author Riya Singh
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Introduction

In programming, particularly in scenarios involving mathematical calculations, the need to round down numbers to the nearest integer or a specific decimal precision is common. Lodash, a popular JavaScript utility library, addresses this need with the _.floor() method.

Lodash _.floor() Method

This method provides an efficient way to round numbers down, complementing the native JavaScript rounding capabilities with enhanced functionality and precision control.

Why This Function is Used

The _.floor() function is used for rounding numbers down to the nearest integer or to a specified decimal place. This method is particularly useful in financial calculations, data reporting, or any other situation where precise rounding down of numbers is required. Unlike the native JavaScript Math.floor() method, which only rounds to the nearest integer, Lodash's _.floor() offers additional flexibility by allowing the specification of precision, making it suitable for a broader range of rounding needs.

Syntax, Parameter and Return Value

Syntax: 

_.floor(number, [precision=0])

Parameters:

  • number (Number): The number to round down.
     
  • [precision=0] (Number): The precision to round down to (number of decimal places).

Return Value: 

(Number) - Returns the rounded down number.

Examples 

Rounding Down to Nearest Integer:

  • JavaScript

JavaScript

var _ = require('lodash');

console.log(_.floor(4.9));
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Output: 

4


Demonstrates rounding a number down to the nearest integer.

Rounding Down with Precision:

  • JavaScript

JavaScript

console.log(_.floor(4.006, 2)); 
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Output: 

4.00


Shows rounding a number down to a specified decimal place.

Financial Calculations:

  • JavaScript

JavaScript

var amount = 1234.567;

var roundedAmount = _.floor(amount, 2); // Rounding down for financial amount

console.log(roundedAmount);
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Output: 

1234.56


An example of using _.floor() in financial calculations to round down an amount.

Using in Array Operations:

  • JavaScript

JavaScript

var numbers = [1.8, 2.9, 3.5];

var roundedNumbers = numbers.map(num => _.floor(num));

console.log(roundedNumbers);
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Output:

[1, 2, 3]


Demonstrates rounding down each number in an array to the nearest integer.

Frequently Asked Questions

How does _.floor() differ from JavaScript's Math.floor()?

While both _.floor() and Math.floor() round numbers down, _.floor() provides the added functionality of specifying the precision to which the number should be rounded down.

Can _.floor() handle negative numbers?

Yes, _.floor() can round negative numbers down (further away from zero) to the specified precision.

Is _.floor() suitable for all numerical rounding needs?

_.floor() is ideal for cases where rounding down is explicitly required. For other types of rounding, other Lodash methods or native JavaScript functions might be more suitable.

Conclusion

Lodash's _.floor() method provides a flexible and precise way to round numbers down, accommodating a variety of scenarios where control over rounding precision is important. It's a valuable tool in financial calculations, data processing, and any situation where specific rounding behavior is required.

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