Size Estimates by Name (Making Choices)
You’re going to write a function to estimate a dinosaur’s mass based on its length. The general form of the equation for doing this is:
mass <- a * length ^ b
The parameters a and b vary by the group of dinosaurs, so you
decide to create a function that lets you specify which dinosaur group you need
to estimate the size of by name and then have the function automatically choose
the right parameters.
Create a new function get_mass_from_length_by_name() that takes 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 use the associated a and b values to estimate the
species mass using these equations:
- Stegosauria:
mass = 10.95 * length ^ 2.64(Seebacher 2001) - Theropoda:
mass = 0.73 * length ^ 3.63(Seebacher 2001) - Sauropoda:
mass = 214.44 * length ^ 1.46(Seebacher 2001)
If the name is not any of these values the function should return NA.
Run the function for:
- A Stegosauria that is 10 meters long.
- A Theropoda that is 8 meters long.
- A Sauropoda that is 12 meters long.
- A Ankylosauria that is 13 meters long.
Challenge (optional): If the name is not one of values that have a and b values print warning that it doesn’t know how to convert that group that includes that groups name in a message like “No known estimation for Ankylosauria”.
You can use the function warning("your warning text") to print a warning and
the function paste() to combine text with a value from a variable paste("My name is", name).
Doing this successfully will modify your answer to (4), which is fine.
Challenge (optional): Change your function so that it uses two different
values of a and b for Stegosauria. When Stegosauria is greater than 8
meters long use the equation above. When it is less than 8 meters long use a =
8.5 and b = 2.8. Run the function for a Stegosauria that is 6 meters
long.