r faq - Use of ~ (tilde) in R programming Language

Question

I saw in a tutorial about regression modeling the following command:

myFormula <- Species ~ Sepal.Length + Sepal.Width + Petal.Length + Petal.Width

What exactly does this command do, and what is the role of ~ (tilde) in the command?

question from:https://stackoverflow.com/questions/65864179/can-someone-explain-the-meaning-of-x-the-context-ive-found-an-example-of

Answer 1

The thing on the right of <- is a formula object. It is often used to denote a statistical model, where the thing on the left of the ~ is the response and the things on the right of the ~ are the explanatory variables. So in English you'd say something like "Species depends on Sepal Length, Sepal Width, Petal Length and Petal Width".

The myFormula <- part of that line stores the formula in an object called myFormula so you can use it in other parts of your R code.

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Other common uses of formula objects in R

The lattice package uses them to specify the variables to plot.
The ggplot2 package uses them to specify panels for plotting.
The dplyr package uses them for non-standard evaulation.