Introduction to Functions and Arguments in R Programming: Part 1

The Beginner’s Guide to Functions in R Programming:

Functions are an essential aspect of programming, and they play a crucial role in R Programming. A function is a set of instructions that are executed when called. It is a way to reuse code and make it more manageable. Functions in R are defined using the function() keyword, and they can take inputs called arguments. In this blog post, we will discuss functions, their arguments, and formal arguments in R Programming.

Arguments in R Functions

Arguments are the inputs that a function takes when it is called. These arguments can be of different types, such as vectors, data frames, or even other functions. In R, arguments are defined within the function's parentheses, and they can have default values. Default values are assigned using the = sign. If a value is not provided for an argument when the function is called, the default value is used. Here is an example of a function that takes two arguments:

my_function <- function(arg1, arg2 = 10) {

  result <- arg1 + arg2

  return(result)

}

In this function, arg1 is a required argument, and arg2 is an optional argument with a default value of 10. If arg2 is not provided when the function is called, it will default to 10. To call this function, we can use the following syntax:

my_function(5) 

# Output: 15

In this example, arg1 is 5, and arg2 is not provided, so it defaults to 10.

Formal Arguments in R Functions

Formal arguments are the names given to the arguments in a function definition. They are used to reference the argument within the function's code. Formal arguments are defined in the function definition, and they must follow the same naming conventions as variable names. In R, formal arguments are defined within the function parentheses, and they can have default values. Here is an example of a function with formal arguments:

my_function <- function(arg1, arg2 = 10) {

  result <- arg1 + arg2

  return(result)

}

In this function, arg1 and arg2 are formal arguments. arg1 is a required argument, and arg2 is an optional argument with a default value of 10.

Practice Material for Beginners

Here are some practice exercises for you to help you master functions in R Programming:

• Write a function that takes a vector as input and returns the sum of all the even numbers in the vector.

• Write a function that takes two vectors as input and returns a new vector that is the result of concatenating the two input vectors.

• Write a function that takes a data frame as input and returns a new data frame that contains only the rows where the value in column A is greater than the value in column B.

• Write a function that takes a list of vectors as input and returns a new list of vectors where each vector has been sorted in ascending order.

• Write a function that takes a function as input and applies it to all the elements in a vector.

• For more practice you should start swirl's lessons in R Programming. Complete download process of swirl and R Programming is here, click on the link!

• You can look in to the practice and reading material that is provided in the text book, click here to download the textbook.

• Lecture slides can be downloaded from here. It would be great if you go through them too.

Conclusion

Functions are an essential aspect of programming, and they play a crucial role in R Programming. They allow for the reuse of code and make it more manageable. Arguments are the inputs that a function takes when it is called, and formal arguments are the names given to the arguments in a function definition. In this blog post, we discussed functions, their arguments, and formal arguments in R Programming, along with some practice material for beginners to help them master functions.