Question

可能重复：
  Iterate a list as pair (current, next) in Python
  Iterating over every two elements in a list

是否可以在Python中以下列方式迭代列表（将此代码视为伪代码）？

a = [5, 7, 11, 4, 5]
for v, w in a:
    print [v, w]

它应该产生

[5, 7]
[7, 11]
[11, 4]
[4, 5]

Answer 1

您可以使用zip功能：

a = [5, 7, 11, 4, 5]
for v, w in zip(a[:-1], a[1:]):
    print [v, w]

Answer 2

来自itertools receipes：

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)

for v, w in pairwise(a):
    ...

Answer 3

要做到这一点，你应该这样做：

a =  [5, 7, 11, 4, 5]
for i in range(len(a)-1):
    print [a[i], a[i+1]]

Answer 4

几乎逐字逐句Iterate over pairs in a list (circular fashion) in Python：

def pairs(seq):
    i = iter(seq)
    prev = next(i)
    for item in i:
        yield prev, item
        prev = item

Answer 5

>>> a = [5, 7, 11, 4, 5]
>>> for n,k in enumerate(a[:-1]):
...     print a[n],a[n+1]
...
5 7
7 11
11 4
4 5

迭代Python列表中的项目对

5 个答案: