根据列表检查输入并附加到列表列表

Question

I have an unordered list, A = [1, 4, 16, 22, 9, 2] and an ordered list p = [0, 6, 12] .

I have created a list of lists s = [ [] for i in range(n+1)] .

I want to compare each element of A against the first element in p , then the second and so on.

If A's element is smaller than p's element I want to append this to the correct list in s . (so first list in s will be empty as nothing is smaller than 0, second list in s should hold 1,4,2. -- Eventually 0 will go into the first list, 6 into the second and 12 into the third. The fourth list will hold elements greater than 12.

(I need it to be generic and work for different list sizes, so A could hold 20 elements and p could hold 5 etc..)

I'm struggling to put this into action. Please help!

Answer 1

Since p is sorted, you can use bisect for this (with O(log(N)) complexity):

for a in A:
    s[bisect.bisect_left(p, a)].append(a)

Out:

[[], [1, 4, 2], [9], [16, 22]]