[dsego]

Why is that cleaner? A for-loop is one of the basic programming constructs.

[mneary]

A for-loop might be a basic programming construct, but it shouldn't be. Mutation and a control flow construct makes for a much worse outlook to the problem than does recursive application of a function.

[agumonkey]

reduce is one very fundamental construct too https://www.google.com/search?q=universality+of+reduce