How Can I Extend Python\'s zip() Function to Handle Iterables of Unequal Lengths?

Extending zip() Functionality: Padding to Longest Length

Python's built-in zip() function pairs elements from multiple iterables, but it truncates the result to the length of the shortest iterable. If you require a more comprehensive zip that pads with None values to align with the longest input, consider the following solutions:

Python 3: itertools.zip_longest

In Python 3, itertools provides the zip_longest() function. It expands the result list to match the length of the longest input.

import itertools
a = ['a1']
b = ['b1', 'b2', 'b3']
c = ['c1', 'c2']

list(itertools.zip_longest(a, b, c))
# [('a1', 'b1', 'c1'), (None, 'b2', 'c2'), (None, 'b3', None)]

You can specify a custom fill value using the fillvalue parameter:

list(itertools.zip_longest(a, b, c, fillvalue='foo'))
# [('a1', 'b1', 'c1'), ('foo', 'b2', 'c2'), ('foo', 'b3', 'foo')]

Python 2: itertools.izip_longest or map None

In Python 2, you can use itertools.izip_longest (introduced in Python 2.6) or employ map with None.

from itertools import izip_longest
a = ['a1']
b = ['b1', 'b2', 'b3']
c = ['c1', 'c2']

list(izip_longest(a, b, c))
# [('a1', 'b1', 'c1'), (None, 'b2', 'c2'), (None, 'b3', None)]

map(None, a, b, c)
# [('a1', 'b1', 'c1'), (None, 'b2', 'c2'), (None, 'b3', None)]

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