[Python-Dev] Typo in itertools.dropwhile()

[Raymond Hettinger]

[Matthieu on itertools.dropwhile() docs]
> Make an iterator that drops elements from the iterable as long as the predicate is true; afterwards, returns every element. Note, 
> the iterator does not produce any output until the predicate is true, so it may have a lengthy start-up time.
>
> It says something and then the opposite, so which one is true ?


It is correct as written.  Given a sequence where predicate is true 1000 times and then alternately false and true, it returns the 
part that is alternately false and true.  So, it did DROP (omit, not return, skip-over, etc) the first 1000 true items and it did 
return EVERY element from the first false to the end.  It did not produce any output for the first 1000 inputs so it took a while to 
get to the first output (the first false).  Hope that clears it up for you.


Raymond