Raymond Hettinger <python <at> rcn.com> writes:
Because there has been limited uptake on {}-formatting (afaict), we still have limited experience with knowing that it is actually better, less error-prone, easier to learn/rember, etc.
It is known to be quite slower. The following timings are on the py3k branch: - with positional arguments: $ ./python -m timeit -s "s='%s %s'; t = ('hello', 'world')" "s % t" 1000000 loops, best of 3: 0.313 usec per loop $ ./python -m timeit -s "f='{} {}'.format; t = ('hello', 'world')" "f(*t)" 1000000 loops, best of 3: 0.572 usec per loop - with named arguments: $ ./python -m timeit -s "s='%(a)s %(b)s'; d = dict(a='hello', b='world')" "s % d" 1000000 loops, best of 3: 0.387 usec per loop $ ./python -m timeit -s "f='{a} {b}'.format; d = dict(a='hello', b='world')" "f(**d)" 1000000 loops, best of 3: 0.581 usec per loop Regards Antoine.