p2 = np.array([1.0, 1.0])
data = np.array([[0.3, 0.6], [0.25, 0.5], [1.0, 0.75]])
```
-Building a Library of Code you Trust
-====================================
+# Building a Library of Code you Trust
Suppose we’re going to be dealing a lot with these animal count files,
and doing many different kinds of analysis with them. In the
has been pulled in using an \`import\` statement. Today we’ll show you
how to do that.
-Exercises
-=========
+## Exercises
-Exercise 1
-----------
+### Exercise 1
Make a new text file called \`animals.py\`. Copy the file reading
function from yesterday’s IPython notebook into the file and modify it
so that it returns the columns of the file as lists (instead of printing
certain lines).
-Exercise 2
-----------
+### Exercise 2
We’re going to make a function to calculate the mean of all the values
in a list, but we’re going to write the tests for it first. Make a new
\`test\_mean\` that runs your theoretical mean function through several
tests.
-Exercise 3
-----------
+### Exercise 3
Write the mean function in \`animals.py\` and verify that it passes your
tests.
-Exercise 4
-----------
+### Exercise 4
Write tests for a function that will take a file name and animal name as
arguments, and return the average number of animals per sighting.
-Exercise 5
-----------
+### Exercise 5
Write a function that takes a file name and animal name and returns the
average number of animals per sighting. Make sure it passes your tests.