How to use interactive coding

What is the interactive coding widget

With the help of DataCamp, we designed our website to include an interactive learning platform that supports both R and Python coding.

In the editor below, you should type R code to solve the exercises. When you hit the ‘Submit’ button, every line of code is interpreted and executed by R, and you receive a message indicating whether or not your code was correct. The outputs of your R codes are shown in the right-hand side R console.

In R, you can use the # sign to add comments, allowing you and others to understand what the R code is about. Just like Twitter! Comments are not run as R code, so they will not influence your result. For example, ‘# Calculate 3 + 4’ in the editor is a comment.”

You can also execute R commands directly in the right-hand side console. This is a good way to experiment with R code, as your submission is not checked for correctness.

How it works: An R exercise

# no pec


        # Calculate 3 + 4
        3 + 4

        # Calculate 6 + 12


        # Calculate 3 + 4
        3 + 4

        # Calculate 6 + 12
        6 + 12


        test_output_contains("18", incorrect_msg = "Make sure to add `6 + 12`
        on
        a new line. Do not start the line with a `#`, otherwise your R code is not executed!")
        success_msg("Awesome! See how the console shows the result of the R code you
        submitted? Now that you're familiar with the interface, let's get down to R
        business!")

Just add a line of R code that calculates the sum of 6 and 12, just like the example in the sample code!

Instructions:

In the editor above there is already some sample code. Can you see which lines are actual R code and which are comments?

Add a line of code that calculates the sum of 6 and 12, and hit the ‘Submit’ button.

An exercise

Economic Order Quantity Model: $Q= \sqrt{2DK/h}$

D=5000: annual demand quantity

K=$4: fixed cost per order

h=$0.5: holding cost per unit

Q=?

Economic Order Quantity Model

# no pec


        # D=5000: annual demand quantity
        D <- 5000
        # K=$4: fixed cost per order
        K <- 
        
        # h=$0.5: holding cost per unit
        h <- 
        
        # Q=?
        Q <-


        # D=5000: annual demand quantity
        D <- 5000
        # K=$4: fixed cost per order
        K <- 4
        
        # h=$0.5: holding cost per unit
        h <- 0.5
        
        # Q=?
        Q <- sqrt(2*D*K/h)
        Q


        test_object("D",
                    undefined_msg = "Please make sure to define a variable `D`.",
                    incorrect_msg = "Make sure that you assign the correct value to `D`.")
        test_object("K",
                    undefined_msg = "Please make sure to define a variable `K`.",
                    incorrect_msg = "Make sure that you assign the correct value to `K`.")
        test_object("h",
                    undefined_msg = "Please make sure to define a variable `h`.",
                    incorrect_msg = "Make sure that you assign the correct value to `h`.")
        test_object("Q",
                    undefined_msg = "Please make sure to define a variable `Q`.",
                    incorrect_msg = "Make sure that you assign the correct value to `Q`.")

        test_output_contains("Q", 
                    incorrect_msg = "Have you explicitly told R to print out the `Q` 
                                    variable to the console?")
        success_msg("Great! Continue to the next exercise!")

Add lines of R codes to save these given numbers, then follow the formula to calculate the order quantity Q!

An python exercise with a plot output

An python exercise with a plot


        import numpy as np
        import matplotlib.pyplot as plt

        x = np.arange(0, 5, 0.1);
        y = np.sin(x)
        plt.plot(x, y)
        plt.show()

Just press 'Run'.