Microbenchmark of small string concatenation methods in Python 2.7.5, Python 3.3.2, and pypy-2.1.

str-concat.py

# Microbenchmark of small string concatenation methods in Python 2.7.5, Python 3.3.2, and pypy-2.1

## Python 2.7.5
In [1]: %timeit '{0}/{1}'.format('taco', 'bell')
1000000 loops, best of 3: 226 ns per loop

In [2]: %timeit '{}/{}'.format('taco', 'bell')
1000000 loops, best of 3: 366 ns per loop

In [3]: %timeit '%s/%s' % ('taco', 'bell')
10000000 loops, best of 3: 174 ns per loop

In [4]: %timeit 'taco' + '/' + 'bell'
10000000 loops, best of 3: 30.4 ns per loop

## Python 3.3.2
In [1]: %timeit '{0}/{1}'.format('taco', 'bell')
1000000 loops, best of 3: 250 ns per loop

In [2]: %timeit '{}/{}'.format('taco', 'bell')
1000000 loops, best of 3: 406 ns per loop

In [3]: %timeit '%s/%s' % ('taco', 'bell')
100000000 loops, best of 3: 18.1 ns per loop

In [4]: %timeit 'taco' + '/' + 'bell'
100000000 loops, best of 3: 18.5 ns per loop

## pypy-2.1
In [1]: %timeit '{0}/{1}'.format('taco', 'bell')
100000000 loops, best of 3: 2.62 ns per loop

In [2]: %timeit '{}/{}'.format('taco', 'bell')
100000000 loops, best of 3: 2.62 ns per loop

In [3]: %timeit '%s/%s' % ('taco', 'bell')
100000000 loops, best of 3: 2.61 ns per loop

In [4]: %timeit 'taco' + '/' + 'bell'
100000000 loops, best of 3: 2.62 ns per loop