raymondh

    The Zen of Python, by Tim Peters

    Beautiful is better than ugly.
    Explicit is better than implicit.
    Simple is better than complex.
    Complex is better than complicated.
    Flat is better than nested.
    Sparse is better than dense.
    Readability counts.
    Special cases aren't special enough to break the rules.
    Although practicality beats purity.
    Errors should never pass silently.
    Unless explicitly silenced.
    In the face of ambiguity, refuse the temptation to guess.
    There should be one-- and preferably only one --obvious way to do it.
    Although that way may not be obvious at first unless you're Dutch.
    Now is better than never.
    Although never is often better than *right* now.
    If the implementation is hard to explain, it's a bad idea.
    If the implementation is easy to explain, it may be a good idea.
    Namespaces are one honking great idea -- let's do more of those!

        def tee(iterable, n=2):
            iterator = iter(iterable)
            shared_link = [None, None]
            return tuple(_tee(iterator, shared_link) for _ in range(n))

        def _tee(iterator, link):
            try:
                while True:
                    if link[1] is None:
                        link[0] = next(iterator)
                        link[1] = [None, None]
                    value, link = link
                    yield value
            except StopIteration:
                return

    from random import Random
    from math import ldexp

    class FullRandom(Random):

        def random(self):
            mantissa = 0x10_0000_0000_0000 | self.getrandbits(52)
            exponent = -53
            x = 0
            while not x:
                x = self.getrandbits(32)
                exponent += x.bit_length() - 32
            return ldexp(mantissa, exponent)

    Variable and attribute read access:
       1.9 ns read_local
       2.4 ns read_nonlocal
       2.8 ns read_global
       4.1 ns read_builtin
       5.0 ns read_classvar_from_class
      12.1 ns read_classvar_from_instance
       4.8 ns read_instancevar
       4.7 ns read_instancevar_slots
      12.2 ns read_namedtuple
      29.0 ns read_boundmethod

    Variable and attribute write access:
       2.4 ns write_local
       2.5 ns write_nonlocal
      10.5 ns write_global
      26.8 ns write_classvar
       4.3 ns write_instancevar
       4.2 ns write_instancevar_slots

    Data structure read access:
       5.7 ns read_list
      11.1 ns read_deque
      10.1 ns read_dict
      10.5 ns read_strdict

    Data structure write access:
       6.2 ns write_list
      11.3 ns write_deque
      11.2 ns write_dict
      12.0 ns write_strdict

    Stack (or queue) operations:
      18.4 ns list_append_pop
      17.8 ns deque_append_pop
      18.1 ns deque_append_popleft