python代码有替代的有效方法吗？

Question

Below is the one I tried. I am looking for an easiest and efficient alternative way. Any help would be appreciated

y = [None] * 620
for i in range(0,204):
    y[i] = 3
for i in range(204,419):
    y[i] = 1
for i in range(419,620):
    y[i] = 2

Answer 1

y = [3] * 204 + [1] * (419 - 204) + [2] * (620 - 419)怎么样？

Answer 2

In general you can do something like this:

stops = [204, 419, 620]
nums = [3, 1, 2]

array = []
for i in range(total_length):
    if i < stops[0]:
        array.append(nums[0])
    elif i < stops[1]:
        array.append(nums[1])
    # more elifs go here
    else:
        array.append(nums[-1])

Answer 3

您可以使用列表理解

[ 3 if x >= 0 and x < 204 else 1 if x >= 204 and x < 419 else 2 for x in range(0, 620)]