R Exercises | Programming Exercises for Finance in the R Language

Introduction to R: Exercises

2. Defining variables. You are given a bond dataset that contains five variables: rate, rating, default, company, and risk_free. Define two new variables: id and excess_return.

The variable id is defined by concatenating the company and rating vectors using the paste() function.

The variable excess_return is defined by subtracting risk_free from rate.


                                risk_free <- c(2.02, 2.02)
                                rate <- c(11.05, 3.01)
                                rating <- c("C","AA")
                                default <- c(TRUE, FALSE)
                                company <- c("Reckless_Corp", "Cautious_Corp")



                            # Concatenate company and rating.
                            paste(company, ___)

                            # Repeat first step; assign output to id.
                            ___ <- ___(___, ___)

                            # Subtract risk_free from rate.
                            ___ - ___

                            # Compute excess return and assign it to id.
                            excess_return <- ___


                            # Concatenate company and rating.
                            paste(company, rating)

                            # Repeat first step; assign output to id.
                            id <- paste(company, rating)

                            # Subtract risk_free from rate.
                            rate - risk_free

                            # Repeat first step; assign output to id.
                            excess_return <- rate - risk_free


                            test_error()
                            test_object("id", incorrect_msg="Recall that you should use the function `paste()` and the variables `company` and `rating` to define `id`.")
                            test_object("excess_return", incorrect_msg="Did you define `excess_return` correctly?")
                            success_msg("Good job! Try printing id to the console to see how company and rating were concatenated.")

Use the paste() function to concatenate strings across two vectors.

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