# How to Round Down in R

When doing data science, it is sometimes necessary to round down to produce round numbers. There are several ways of carrying out this task some will always round down while others will sometimes round up. Using these functions properly result in the functions rounding down for the proper numeric values. Rounding down will always result in a smaller number than the original.

### Options for Rounding Down a Number in R

When you want to round down a number, r has several rounding functions Including the mround function, rounddown function, floor function, and round function. The round function will round down to the last integer when the value after the decimal point is less than five. The floor function will always round down to the last integer. In each case, you end up with an integer. The goal of rounding down numbers is to eliminate excess and insignificant digits from the number you are working with. The result is that it simplifies the numbers you are trying to evaluate.

### How It Works – Rounding Down a Number in R

With the round function we round the number off to the nearest integer whether it rounds up or down depending upon the digit following the decimal place. The floor function will simply reduce the value to the previous integer value. Rounding down always produces a lower value than the one you started with. As a result, positive numbers will always get closer to zero while negative numbers, will get more negative. When set up right these functions will produce the results you are looking for, but the floor function is the only one that always rounds down but the trunc function will round up with a negative number.

### Examples of R Functions That Round Down Numbers

Here are five examples of functions that round down numbers. They each produce different effects and most of them will round up under certain circumstances.

> x = c(1.3, 2.4, 3.2, 11.1, 55.3, 110.2, 776.1)
> round(x)
[1] 1 2 3 11 55 110 776

In this example, we use the round down the values in vector x.In this situation, the function rounds the number down to the next lower integer.

> x = c(1.7, 2.3, 3.4, 11.8, 55.6, 110.4, 776.8)
> floor(x)
[1] 1 2 3 11 55 110 776

In this example, we use the floor function to round down the values in the vector x.

> library(“plyr”)
> x = c(1.7, 2.3, 3.4, 11.8, 55.6, 110.4, 776.8)
> round_any(x, 10, f = floor)
[1] 0 0 0 10 50 110 770

In this example, we use the round_any function to round the values of vector x down to the next lower multiple of ten.

> x = c(1.2, 2.3, 3.4, 12.2, -56.4, 123.9, 726.8)
> signif(x, digits = 1)
[1] 1 2 3 10 -60 100 700

In this example, we use the signif function to round the values of vector x down to a set significant figure. In this particular case, we are rounding down to a single significant digit.

> x = c(1.7, 2.3, 3.4, 11.8, 55.6, 110.4, 776.8)
> trunc(x)
[1] 1 2 3 11 55 110 776

In this example, we use the trunc function to round the values in the vector x down. If a value had been negative, it would have resulted in the negative number being rounded up.

### Applications of Rounding Down Numbers

The application of rounding down numbers is a matter of controlling the number of digits. In most cases, the result is an integer value and so it eliminates the need for dealing with fractions.

Rounding down numbers is a straightforward process in r programming. The only challenge is learning the different functions you can use for different circumstances.

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