Once you've exhausted all the low-hanging fruit, like people calling .keys() on dicts, or doing unnecessary linear searches, Cython really starts to shine. I've seen it perform ~40 times better than pure Python in time-consuming loops.
We do scientific computing at my company. Numpy does 90% of the work, but there are some algorithms that just aren't easily expressed with arrays. That's where Cython comes in.
We do scientific computing at my company. Numpy does 90% of the work, but there are some algorithms that just aren't easily expressed with arrays. That's where Cython comes in.