How to get the length of an itertools.product?

Question

I am using itertools to run a numerical simulation iterating over all possible combinations of my input parameters. In the example below, I have two parameters and

Answer 1

While this doesn't answer the question directly, very often we want to find the length of generators to estimate the progress/runtime.

For this, do consider using tqdm's (version >= 4.42.0) wrappers around generator functions that don't forget the lengths of iterators (tqdm is a progressbar library). E.g.,

from tqdm.contrib.itertools import product
from time import sleep
for i, j in product(range(3), range(4)):
    sleep(1)

will show a progress bar. The length of the product is shown as the total of the tqdm object (e.g.., the 6 in 3/6 [00:03<00:03] shown).