Here’s an example of a piecewise function with 3 "pieces" (or "conditions"):
# species-dot :: (Row) -> Image
fun species-dot(r):
if (r["species"] == "dog"): square(5, "solid", "black")
else if (r["species"] == "cat"): square(5, "solid", "orange")
else if (r["species"] == "lizard"): square(5, "solid", "green")
end
end| What do you Notice about this code? | What do you Wonder? |
|---|---|
1 What will this function produce for a dog?
2 What will this function produce for a cat?
Open the Piecewise Displays Starter File, and click "Run".
3 Compare the regular scatter plot with the image scatter plot. What can you see now that you couldn’t see before?
4 Compare the regular histogram with the image histogram. What can you see now that you couldn’t see before?
5 What do you think will happen if we run the function on a species that it has no condition for?
6 On line 45, add a comment (#) to "turn off" the condition for snails. Click Run and test your prediction. In your own words, describe how piecewise / conditional functions work.
★ Optional: Make a new function (don’t delete species-dot!), which uses piecewise functions to draw something different! For example, have it draw different shapes depending on whether an animal is younger than 3 years old or not.
These materials were developed partly through support of the National Science Foundation, (awards 1042210, 1535276, 1648684, 1738598, 2031479, and 1501927). 
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