performance/benchmarks/bm_nbody.py
def combinations(l):
    """Pure-Python implementation of itertools.combinations(l, 2)."""
    result = []
    for x in xrange(len(l) - 1):
        ls = l[x + 1:]
        for y in ls:
            result.append((l[x], y))
    return result
def combinations(l):
    """Pure-Python implementation of itertools.combinations(l, 2)."""
    result = []
    for x in xrange(len(l) - 1):
        ls = l[x + 1:]
        for y in ls:
            result.append((l[x], y))
    return result
Pure-Python implementation of itertools.combinations(l, 2).