Size Estimates By Name Apply (Loops)

This is a followup to Size Estimates by Name.

Download the data on dinosaur lengths with species names into your data folder and import it using read.csv().

Write a function get_mass_from_length_by_name() that uses the equation mass <- a * length^b to estimate the size of a dinosaur from its length. This function should take two arguments, the length and the name of the dinosaur group. Inside this function use if/else if/else statements to check to see if the name is one of the following values and if so set a and b to the appropriate values.

• Stegosauria: a = 10.95 and b = 2.64 (Seebacher 2001).
• Theropoda: a = 0.73 and b = 3.63 (Seebacher 2001).
• Sauropoda: a = 214.44 and b = 1.46 (Seebacher 2001).

If the name is not any of these values set a = NA and b = NA.

1. Use this function and mapply() to calculate the estimated mass for each dinosaur. You’ll need to pass the data to mapply() as single vectors or columns, not the whole data frame.

2. Using dplyr, add a new masses column to the data frame (using rowwise(), mutate() and your function) and print the result to the console.

3. Using ggplot, make a histogram of dinosaur masses with one subplot for each species (using facet_wrap()).

Expected outputs for Size Estimates By Name Apply: 1 2