I find that about 90% of the time I want want to zip iterators together, I
expect them to be the same length and want to throw an exception if they
aren't. Yet there is not currently a solution for this in the standard
library for this, and as a result I always have to take this function
everywhere I go:
def zip_equal(*iterables):
"""
Zip and raise exception if lengths are not equal.
Taken from solution by Martijn Pieters, here:
http://stackoverflow.com/questions/32954486/zip-iterators-asserting-for-equal-length-in-python
:param iterables: Iterable objects
:return: A new iterator outputting tuples where one element comes
from each iterable
"""
sentinel = object()
for combo in zip_longest(*iterables, fillvalue=sentinel):
if any(sentinel is c for c in combo):
raise ValueError('Iterables have different lengths.
Iterable(s) #{} (of 0..{}) ran out first.'.format([i for i, c in
enumerate(combo) if c is sentinel], len(combo)-1))
yield combo
Would anybody object to adding this to the standard library for Python 3.8?
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