On Jan 22, 1:19 pm, Alan Isaac <[EMAIL PROTECTED]> wrote:
[...]
> PS My understanding is that the behavior
> of the last is implementation dependent
> and not guaranteed.
[...]
> def pairs4(x):
> xiter = iter(x)
> for x12 in izip(xiter,xiter):
> yield x12
According to the docs [1], izip is defined to be equivalent to:
def izip(*iterables):
iterables = map(iter, iterables)
while iterables:
result = [it.next() for it in iterables]
yield tuple(result)
This guarantees that it.next() will be performed from left to right,
so there is no risk that e.g. pairs4([1, 2, 3, 4]) returns [(2, 1),
(4, 3)].
Is there anything else that I am overlooking?
[1] http://docs.python.org/lib/itertools-functions.html
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Arnaud
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