python - 在python中链接两个不同长度的相关列表

Question

我有两个整数列表：例如

a = [ 008, 016, 024... ]

b = [001, 002, 002, 003... 012, 016]

列表 a 一致地递增 8，而列表 b 更随机（例如，有时两个记录的整数）。

基本上我想要做的是产生一个连接这两者的字典，这样 a[i] = b[i] <= a[i+1] 它被附加到这样的？

所以我会从 b 得到：

c = [ 008, 008, 008, 008 ... 016, 016]

希望这是有道理的？

Answer 1

I guess you're looking for something like this:

>>> a = [ 8, 16, 24, 32 ]
>>> b = [1, 2, 2, 3, 12, 16]
>>> [a[0] if a[0] < x and [a.pop(0)] else a[0] for x in b ]
[8, 8, 8, 8, 16, 16]

Using collections.deque:

>>> from collections import deque
>>> d = deque(a)
>>> [d[0] if d[0] < x and [d.popleft()] else d[0] for x in b ]
[8, 8, 8, 8, 16, 16]

A much read-able version:

>>> it = iter(a)
>>> prev = next(it)
>>> result = []
for x in b:
    if x <= prev:
        result.append(prev)
    else:
        prev = next(it)
        result.append(prev)
...         
>>> result
[8, 8, 8, 8, 16, 16]

Answer 2

作为生成器：

def make_c(a, b):
    a_idx = 0
    for elt in b:
        # while loop can be replaced with "if"
        # as long as jumps in b never skip elements in a
        while elt > a[a_idx]: 
            a_idx += 1
        yield a[a_idx]