Should I Cache Range Results If I Reuse Them?

I'm relatively new to python, and I'm trying to optimize some code for a HackerRank problem. I found it odd that using range (i.e. generating a list?) is faster than just using a w

Solution 1:

In python 3, range is a generator. It means that it will yield all the numbers of the sequence. It's simple additions.

You could cache that in a list: cache = list(range(10)) but that would allocate some memory and would need to iterate on it: not productive!

BTW: the first example does not cache the result, you just copy the generator function. You may save a few microseconds of parsing time (because the function is already parsed, not really worth it)

So, no, it is not useful to cache the result of range in python 3 (in python 2, it would be useful, yes, since it creates an actual list).

Solution 2:

It won't make a noticeable difference, the majority of the time is spent inside of the loop, not generating the range object.

range in Python 3 returns a sequence, which means it will generate the values on the fly, without having to store them in a list.