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What is the use of the"zip_longest" function in Python?

In Python, the zip_longest() function is part of the itertools module and is used to create an iterator that aggregates elements from multiple iterables, filling in missing values with a specified fill value. It is similar to the zip() function, but it handles iterables of different lengths by providing a default value for missing elements.

The zip_longest() function takes two or more iterables as arguments and returns an iterator that generates tuples containing elements from each iterable. If the iterables are of different lengths, the missing values are filled with a specified fillvalue (which defaults to None).

Here's an example to demonstrate the usage of the zip_longest() function:

import itertools

list1 = [1, 2, 3]
list2 = ['A', 'B']
list3 = ['X', 'Y', 'Z']

zipped_iterator = itertools.zip_longest(list1, list2, list3)

for item in zipped_iterator:
    print(item)

# Output:
# (1, 'A', 'X')
# (2, 'B', 'Y')
# (3, None, 'Z')

In this example, the zip_longest() function aggregates elements from list1, list2, and list3 into tuples. Since list2 is shorter than the other lists, it fills in the missing values with the default fillvalue (which is None by default).

The zip_longest() function is useful when you need to combine elements from multiple iterables, even if they have different lengths. It allows you to work with uneven or mismatched data and ensures that corresponding elements are aligned in the resulting tuples. By providing a fillvalue, you can control the default value for missing elements.

It's important to note that the zip_longest() function continues generating tuples until the longest iterable is exhausted. If you only want to iterate up to the length of the shortest iterable, you can use the zip() function instead.

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