 # logit function in R: How To Perform The Generalized Logit Function

In this article, we will share with you the definition, the syntax and how to use the logit function in R. This function is very useful when analyzing data. Let’s learn more about the logit() function with the explanation and examples below.

## Logit Function In R

### What does the logit() function do in R?

Before learning the logit() function in R, we will show you the theory of this function to calculate it by hand. This function is defined as follows:

• min: The minimum value of an R object.
• max: The maximum value of an R object.
• x: The initial value of the object.
• y: The value after performing the logit function.

And the logit() function is built in the ‘gtools’ package in R to perform the generalized logit function. Let’s take a look at the syntax of the logit() function in R.

### Syntax

logit(x, min, max)

Parameters

• x: The R object.
• min: The default is 0. You can specify this value, but normally, it is the minimum of the object.
• max: The default is 1. You can specify this value, but normally, it is the maximum of the object.

After learning the definition and syntax of the logit() function, you will learn how to perform it in R in the next title below.

## How To Use The Logit Function In R

The logit function is used with the numeric object to find the values of each element based on the generalized logit function.

### Set up the environment

The logit() function is built in the ‘gtools’ package, so you have to install this package first to perform the logit() function.

Run the following statement to install the 'gtools' package.

install.packages('gtools')

### Use the logit() function with the vector

You can use the logit() function to find the values of each element based on the generalized logit function.

Look at the example below.

library(gtools)

# Create the vector.
vec <- c(5, 7, 11, 13.5, 14, 12)

# Perform the logit function.
logit(vec, min = 5, max = 14)

Output

 -Inf -1.2527630 0.6931472 2.8332133 Inf 1.2527630

### Use the logit() function with the matrix

You can use the logit() function to find the values of each element based on the generalized logit function in the matrix.

Look at the example below.

library(gtools)

# Create the matrix.
mat <- matrix(1:12, nrow = 4, ncol = 3)

# Perform the logit function.
logit(mat, min = 2, max = 12)

Output

      [,1] [,2] [,3]
[1,] NaN -0.8472979 0.8472979
[2,] -Inf -0.4054651 1.3862944
[3,] -2.197225 0.0000000 2.1972246
[4,] -1.386294 0.4054651 Inf


Note the elements whose values are not in the range [min, max] then the result will be NaN.

Thus, the logit() function can be applied to the data frame. But this case is rare because the data in the data frame is often used for many different purposes.

Besides, click here if you are interested in survival analysis with the log-rank test in R.

## Summary

We have shown you the theory, the usage, and which ways and data structures should apply the logit function in R. If you have any questions about this tutorial, leave your comment below, and I will answer your questions. Thanks!

Posted in R