Thread by @__mharrison__

Here's a crazy piece of Python code (from @driscollis) illustrating how to calculate prime numbers below 1000 in a "functional" style.

How would I write this?

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Functional programming like this can be great for minimizing lines of code. But it is also great for making your brain spin. Here is how I would initially write this (if I were fancy, I would use the Sieve of Eratosthenes):

Can we collapse this into fewer lines of code? Certainly, (the functional style already showed that) we can. One thing to realize is that lines 3-6 can be replaced with an any call:

At this point, the code is structured such that we can use a list comprehension (or generator expression). Alternatively,
we could parameterize the code into a function and convert it to a generator. Let's see the list comprehension:

Let's make it into a function:

Recognizing that the function is accumulating, we can convert it into a generator by replacing the .append call with yield, or converting the list comprehension version into a generator expression:

What code do I prefer? I try to focus on making readable code. While I understand comprehensions, I don't favor complex comprehensions and I would probably write out the for loop. Just because you can write less lines of code doesn't mean that you always should.

Thanks for reading!

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