R Exercises | Programming Exercises for Finance in the R Language

Introduction to R: Exercises

8. Extending a data frame. In some cases, we will want to extend a data frame by adding another column. We will often do this after transforming a variable. You can add a column to the dataframe df with the syntax df$column_name = variable.

You are given a data frame, bond_data that contains two columns: rate and risk_free. Compute the excess return and assign it to a column named excess_return.


                                bond_data = data.frame(
                                risk_free = c(2.02, 2.02),
                                rate <- c(11.05, 3.01)
                                )



                            # Define a variable for the excess_return.
                            excess_return <- bond_data$rate - ___

                            # Create new column for excess_return in bond_data.
                            ___$excess_return <- ___

                            # Print data frame.
                            ___(bond_data)



                            # Define a variable for the excess_return.
                            excess_return <- bond_data$rate - bond_data$risk_free

                            # Create new column for excess_return in bond_data.
                            bond_data$excess_return <- excess_return

                            # Print data frame.
                            print(bond_data)


                            test_error()
                            test_object("excess_return", incorrect_msg="Did you compute the excess return correctly?")
                            test_function("print", incorrect_msg="Did you use the `print()` function?")
                            success_msg("Well done!")

Remember that you can assign the variable X to the dataframe df using the syntax df$X=X.

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