使用for循环创建反向编号列表

Question

I have this function.

def creates(n): 
    output = []
    for i in range(1, n+1):
        output.append(range(-1, i-1))
    return output

I want it to return [[1],[2,1],[3,2,1],[4,3,2,1]] when I print creates(4) without using a reverse function in the code. I know it's possible and I feel like I am using append incorrectly but I don't know where the issue is. Thanks!

Answer 1

You mean to do:

output.append(range(i, 0, -1))

Since range(4, 0, -1) (for example) returns [4, 3, 2, 1] .

Note that this could be written in fewer lines as a list comprehension:

def creates(n):
    return [range(i, 0, -1) for i in range(1, n+1)]