On 11/2/2016 6:03 PM, Francisco Couzo wrote:
Some functions that take a predicate from itertools accept None as its
predicate:
list(itertools.filterfalse(None, range(10)))
[0]
list(itertools.groupby([0,0,1,1], None))
[(0, <itertools._grouper object at 0x7fedc2047198>), (1,
<itertools._grouper object at 0x7fedc2
0471d0>)]
While others don't:
list(itertools.dropwhile(None, range(10)))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'NoneType' object is not callable
I'd be interested in writing a patch to make itertools more consistent
if there's a consensus.
I see two possible solutions:
* Either remove None as a predicate parameter, which would not be
backwards compatible.
* Or make the functions that don't accept None start accepting it.
I think you should post this as an enhancement proposal on the tracker.
Put Raymond Hettinger, the itertools originator and maintainer, as nosy.
--
Terry Jan Reedy
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