Daniel Arbuckle's Mastering Python

Using cpdef in a Cython class

In the following code example, you'll see that we're getting to the reason why we called our class StatisticalArray. We implemented several discrete statistical calculations using the values stored in the class instance. You don't need to worry about what mean, variance, and covariance actually do, but let's take a look at how they're actually working.

In the mean function, here, we see a loop that calculates the sum of the values stored in the array. If we were running that code in Python, each cycle through the loop would involve several dictionary lookups and function calls. Cython generates four lines of C ...