Python中有類似Ruby的#each_cons功能嗎？

今天小編為大家?guī)淼氖荘ython中有類似Ruby的#each_cons功能嗎？

在Ruby中你可以這樣做:

array = [1,2,3,4]
array.each_cons(2).to_a
=> [[1,2],[2,3],[3,4]]

對于此類內(nèi)容，您應(yīng)該查看的模塊是：itertools

from itertools import tee, izip

def pairwise(iterable):
    "s -> (s0,s1), (s1,s2), (s2, s3), ..."
    a, b = tee(iterable)
    next(b, None)
    return izip(a, b)

然后：

>>> list(pairwise([1, 2, 3, 4]))
[(1, 2), (2, 3), (3, 4)]

對于更通用的解決方案，請考慮：

def split_subsequences(iterable, length=2, overlap=0):
    it = iter(iterable)
    results = list(itertools.islice(it, length))
    while len(results) == length:
        yield results
        results = results[length - overlap:]
        results.extend(itertools.islice(it, length - overlap))
    if results:
        yield results

這允許任意長度的子順序和任意重疊。用法：

>> list(split_subsequences([1, 2, 3, 4], length=2))
[[1, 2], [3, 4]]
>> list(split_subsequences([1, 2, 3, 4], length=2, overlap=1))
[[1, 2], [2, 3], [3, 4], [4]]

這樣就可以達(dá)到類似的效果了。