Python's "only one way to do it" philosophy isn't good?

[Hrvoje Niksic]

Douglas Alan <doug at alum.mit.edu> writes:

> I think you overstate your case.  Lispers understand iteration
> interfaces perfectly well, but tend to prefer mapping fuctions to
> iteration because mapping functions are both easier to code (they
> are basically equivalent to coding generators) and efficient (like
> non-generator-implemented iterators).  The downside is that they are
> not quite as flexible as iterators (which can be hard to code) and
> generators, which are slow.

Why do you think generators are any slower than hand-coded iterators?
Consider a trivial sequence iterator:

$ python -m timeit -s 'l=[1] * 100
class foo(object):
  def __init__(self, l):
    self.l = l
    self.i = 0
  def __iter__(self):
    return self
  def next(self):
    self.i += 1
    try:
      return self.l[self.i - 1]
    except IndexError:
      raise StopIteration
' 'tuple(foo(l))'
10000 loops, best of 3: 173 usec per loop

The equivalent generator is not only easier to write, but also
considerably faster:

$ python -m timeit -s 'l=[1] * 100
def foo(l):
  i = 0
  while 1:
    try:
      yield l[i]
    except IndexError:
      break
    i += 1
' 'tuple(foo(l))'
10000 loops, best of 3: 46 usec per loop