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Zipping two iterators until they are both exhausted

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Similar to the built-in function zip(), itertools.zip_longest will continue iterating beyond the end of the shorter of two iterables. 

from itertools import zip_longest
a = [i for i in range(5)] # Length is 5
b = ['a', 'b', 'c', 'd', 'e', 'f', 'g'] # Length is 7
for i in zip_longest(a, b):
    x, y = i  # Note that zip longest returns the values as a tuple
    print(x, y)

An optional fillvalue argument can be passed (defaults to '') like so: 

for i in zip_longest(a, b, fillvalue='Hogwash!'):
    x, y = i  # Note that zip longest returns the values as a tuple
    print(x, y)

In Python 2.6 and 2.7, this function is called itertools.izip_longest.

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Itertools Module:
* Itertools Module
* itertools.dropwhile
* Combinations method in Itertools Module
* Take a slice of a generator
* Zipping two iterators until they are both exhausted
* Grouping items from an iterable object using a function
* itertools.takewhile
* itertools.count
* itertools.product
* itertools.repeat
* Get an accumulated sum of numbers in an iterable
* Cycle through elements in an iterator
* itertools.permutations
* Chaining multiple iterators together
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184 Python Lex-Yacc
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189 Raise Custom Errors Exceptions
190 Using loops within functions
191 Contributors