Most efficient way to take sequential substrings python

Question

Let's say I have abcdefgh. I want all the sequential substrings of length k. So for this string if k = 4, I would want abcd bcde cdef defg efgh. I would just loop through with the indices, but is there a more "pythonic" way?

Answer 1

How about:

In [13]: s = "abcdefgh"

In [14]: [s[i:i+4] for i in xrange(len(s)-3)]
Out[14]: ['abcd', 'bcde', 'cdef', 'defg', 'efgh']

Still a loop, but wrapped in a list comprehension.

Or, if you want to get fancy:

In [18]: map(''.join, zip(*(s[i:] for i in range(4))))
Out[18]: ['abcd', 'bcde', 'cdef', 'defg', 'efgh']

(Personally, I wouldn't use the latter as it's rather obtuse.)