Python中有类似Ruby的#each_cons功能吗？

今天小编为大家带来的是Python中有类似Ruby的#each_cons功能吗？

在Ruby中你可以这样做:

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

对于此类内容，您应该查看的模块是：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)]

对于更通用的解决方案，请考虑：

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

这允许任意长度的子顺序和任意重叠。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]]

这样就可以达到类似的效果了。