How Can I Efficiently Implement a Rolling or Sliding Window Iterator in Python?

Rolling or Sliding Window Iterator

Rolling or sliding window iterators enable the traversal of a sequence in overlapping windows of a specified size. Iterating over a sequence with a window size of 1 is essentially the default Python iteration.

Efficient and Elegant Implementation

The following implementation from the Python documentation leverages the itertools module for increased efficiency:

from itertools import islice

def window(seq, n=2):
    """Returns a sliding window (of width n) over data from the iterable"""
    "s -> (s0,s1,...s[n-1]), (s1,s2,...,sn), ..."
    it = iter(seq)
    result = tuple(islice(it, n))
    if len(result) == n:
        yield result
    for elem in it:
        result = result[1:] + (elem,)
        yield result

Implementation for Simple Iterables

For iterables represented as simple lists or tuples, a straightforward approach involves iterating through the iterable with the specified window size:

seq = [0, 1, 2, 3, 4, 5]
window_size = 3

for i in range(len(seq) - window_size + 1):
    print(seq[i: i + window_size])

Output:

[0, 1, 2]
[1, 2, 3]
[2, 3, 4]
[3, 4, 5]

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