Python Split String In Moving Window

I have a string with digits like so - digit = '7316717' Now I want to split the string in such a way that the output is a moving window of 3 digits at a time. So I get - ['731',

Solution 1:

The itertools examples provides the window function that does just that:

from itertools import islice
defwindow(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))
    iflen(result) == n:
        yield result    
    for elem in it:
        result = result[1:] + (elem,)
        yield result

Example usage:

>>> ["".join(x) for x in window("7316717", 3)]['731', '316', '167', '671', '717']

Solution 2:

>>> s = "7316717">>> [s[i:i+3] for i inrange(len(s)-2)]
['731', '316', '167', '671', '717']

Solution 3:

There is a very good recipe pairwise in itertools docs.

Modernizing it a bit for n elements in the group, I made this code:

from itertools import tee, izip

def window(iterable, n):
    els = tee(iterable, n)
    for i, el in enumerate(els):
        for _ in xrange(i):
            next(el, None)
    return izip(*els)


print(["".join(i) for i in window("2316515618", 3)])

Python 2.7

Solution 4:

digit = "7316717"digit_sets = [digit[i:i+3] for i in range(len(digit)-2)]