Split list in special chunks

Question

I have the following problem. I have a list like:

>>> l = list(range(20))
>>> l
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
>>> # What I want:
>>> [[0, 1, 2, 3], [3, 4, 5, 6], [6, 7, 8, 9] , ...]

How can I get my list into such k pieces with length 4 in the most pythonic way? I feel like I miss something obvious here. I am fully aware of How do you split a list into evenly sized chunks? but still have no clue...

Thanks in advance!

Could you expand on what you are struggling with? The referenced answer provides a range of very Pythonic approaches to this problem. — Simon, Oct 13 '13 at 20:31
No, no and no! Note that the last element of each chunk is the same as the first element of the next chunk! — Nikolai Tschacher, Oct 13 '13 at 20:36
@NikolaiTschacher well, you're not chunking your list, you're generating a pattern *similar* to your list. The two problems are not at all the same thing. — roippi, Oct 13 '13 at 20:38

score 2 · Accepted Answer · answered Oct 13 '13 at 20:36

2

A direct copy of an answer to question you have posted link to. The only change is the step in xrange - from n to n - 1:

def chunks(l, n):
    for i in xrange(0, len(l), n - 1):
        yield l[i:i + n]


list(chunks(range(20), 4))
[[0, 1, 2, 3], [3, 4, 5, 6], [6, 7, 8, 9], [9, 10, 11, 12], [12, 13, 14, 15], [15, 16, 17, 18], [18, 19]]

answered Oct 13 '13 at 20:36

Maciej Gol

15,394
4
33
51

Finally someone who read the question correctly. Thanks for the answer and hell yes, I could have figured that one out for myself...Thanks sir! – Nikolai Tschacher Oct 13 '13 at 20:38

score 0 · Answer 2 · answered Oct 13 '13 at 20:32

0

zip(*[iter(list(range(20)))]*4)

answered Oct 13 '13 at 20:32

asdas

23
3

Not what I want. Note that the last element of each chunk is the same as the first element of the next chunk! – Nikolai Tschacher Oct 13 '13 at 20:37

score 0 · Answer 3 · answered Oct 13 '13 at 20:36

0

a = range(20)
b = [a[i:i+4] for i in xrange(0, len(a), 4)]
print b
[[0, 1, 2, 3], [4, 5, 6, 7], [8, 9, 10, 11], [12, 13, 14, 15], [16, 17, 18, 19]]

answered Oct 13 '13 at 20:36

user2876986

11
1

Split list in special chunks

3 Answers3