Question

So I have a function which reduces some dataset, and returns the number of elements removed. I have to stop applying it once the number of items reduced during the function’s operation is zero. Currently I’ve got this:

num_removed = reduction_pass(dataset)
while num_removed > 0:
    num_removed = reduction_pass(dataset)

but these two variable assignments kind of get to me. Is there a more elegant way to write this?

Answer 1

I assume you don’t actually need the final return value, as I assume it indicates the number of removed elements, which will obviously always be 0 on the last pass.

The simple-is-better-than-complex way:

while reduction_pass(dataset) > 0: pass

The showing-off, obviously-not-serious way:

from itertools import *
list(takewhile(lambda x: x > 0, starmap(reduction_pass, repeat((dataset,)))))