How Can I Efficiently Implement Sliding Window Iteration in Python?

Sliding Window Iteration Techniques

For sliding window iteration over an iterable, a basic implementation can use list slicing and iteration:

def rolling_window(seq, window_size):
    it = iter(seq)
    win = [it.next() for cnt in range(window_size)]  # First window
    yield win
    for e in it:  # Subsequent windows
        win[:-1] = win[1:]
        win[-1] = e
        yield win

Efficient and Elegant Solutions

For greater efficiency and elegance, a generator expression with itertools can be employed:

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

For simpler iterables like lists or tuples, a straightforward approach using range and indexing can be used:

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])

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