On Oct 15, 2016 6:42 PM, "Steven D'Aprano" steve@pearwood.info wrote:

doesn't make sense, it is invalid. Call it something else: the new "flatten" operator:

[^t for t in iterable]

for example, which magically adds an second invisible for-loop to your

list comps:

This thread is a lot of work to try to save 8 characters in the spelling of `flatten(it)`. Let's just use the obvious and intuitive spelling.

We really don't need to be Perl. Folks who want to write Perl have a perfectly good interpreter available already.

The recipes in itertools give a nice implementation:

def flatten(listOfLists): "Flatten one level of nesting" return chain.from_iterable(listOfLists)