Fastest way to thousands-commafy large numbers in Python/PyPy

Senyai October 13, 2012 Reply

+20% speed

    def f1(n):
        return ''.join(
            reversed(
                [
                c + ','
                if i != 0 and i % 3 == 0 else
                c
                for i, c in enumerate(reversed(str(n)))
                ]
            )
        )

Peter Bengtsson October 14, 2012 Reply

That looks like f2() but laid out slightly differently.