range countdown to zero

问题

I am taking a beginner Python class and the instructor has asked us to countdown to zero without using recursion. I am trying to use a for loop and range to do so, but he says we must include the zero.

I searched on the internet and on this website extensively but cannot find the answer to my question. Is there a way I can get range to count down and include the zero at the end when it prints?

Edit:

def countDown2(start):
#Add your code here!
    for i in range(start, 0, -1):
        print(i)

回答1:

The range() function in Python has 3 parameters: range([start], stop[, step]). If you want to count down instead of up, you can set the step to a negative number:

for i in range(5, -1, -1):
    print(i)

Output:

5
4
3
2
1
0

回答2:

As another option to @chrisz's answer, Python has a built-in reversed() function which produces an iterator in the reversed order.

start_inclusive = 4
for i in reversed(range(start_inclusive + 1)):
   print(i)

outputs

4
3
2
1
0

This can be sometimes easier to read, and for a well-written iterator (e.g. built-in range function), the performance should be the same.

来源：https://stackoverflow.com/questions/49539187/range-countdown-to-zero