Python中算术序列到切片的转换

我认为如果序列没有统一的步长,你也需要失败。

def seq_to_slice(arr):
    if len(arr) == 1:
        return slice(arr[0], arr[0]+1)
    diff = [arr[num] - arr[num-1] for num in range(1, len(arr))]
    if max(diff) == min(diff):
        step = max(diff)
    else:
        raise ValueError('Sequence cannot be converted to slice')
    step = None if step == 1 else step
    min_arr = None if min(arr) == 0 else min(arr)
    max_arr = max(arr) + 1
    if step and step < 0:
        min_arr, max_arr = max_arr - 1, min_arr - 1 if min_arr else min_arr
    return slice(min_arr, max_arr, step)

seq_to_slice([1,2,5]) # Should fail