What\'s the Most Efficient Way to Perform Element-Wise Addition of Lists in Python?

Element-Wise Addition of Lists: A Pythonic Approach

Adding two lists element-wise can be performed effortlessly in Python using several built-in functions. Here's how to achieve this without cumbersome iterations:

Using map() with operator.add:

from operator import add
result = list(map(add, list1, list2))

The map() function applies the add function to each corresponding element in list1 and list2, returning a list of the results.

Alternatively, using zip() with a list comprehension:

result = [sum(x) for x in zip(list1, list2)]

The zip() function pairs up the elements from list1 and list2 into a sequence of tuples. The list comprehension then calculates the sum of each tuple, producing the element-wise addition.

Performance Comparisons:

To compare the efficiency of these approaches, we conducted timing tests on large lists (100,000 elements):

>>> from itertools import izip
>>> list2 = [4, 5, 6] * 10 ** 5
>>> list1 = [1, 2, 3] * 10 ** 5

>>> %timeit from operator import add; map(add, list1, list2)
10 loops, best of 3: 44.6 ms per loop

>>> %timeit from itertools import izip; [a + b for a, b in izip(list1, list2)]
10 loops, best of 3: 71 ms per loop

>>> %timeit [a + b for a, b in zip(list1, list2)]
10 loops, best of 3: 112 ms per loop

>>> %timeit from itertools import izip; [sum(x) for x in izip(list1, list2)]
1 loops, best of 3: 139 ms per loop

>>> %timeit [sum(x) for x in zip(list1, list2)]
1 loops, best of 3: 177 ms per loop

As these results demonstrate, the map() approach using operator.add is the fastest for large lists.

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