# 10 / 18 Stride Length

#1

Trying to figure out how to get it to come to zero. the second list is mine and I added a comment. If I didnt want to leave the start : finish blank, how would I get it to come to 0. putting it to zero didnt get it to reach to zero, or -1, or -10.

#2

Hello

Why it didn’t get to `0`? Because the second “parameter” of `slice` is an exclusive index, it’s the first index that will be excluded from the resulting list. And `range` works in the same way:

``````range(3, 7):
=> [3, 4, 5, 6]
``````

You see? It does not include `7`.

So why `-1` or `-10` did not work?

In Python negative indices have a special meaning. Index `-1` refers to the last index, index `-2` to the second to last etc.

``````to_one_hundred[100:-15:-2]
=> [100, 98, 96, 94, 92, 90, 88]
``````

how would I get it to come to 0

You can use `None` if the blank space really bothers you.

``````to_one_hundred[100:None:-10]
=> [100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 0]
``````

I would like to emphasize one point. Do not treat `slice` parameters as values, they are indices. Codecademy exercise uses list from `0` to `100` so it might be misleading. Here is an example:

``````test_list = range(0, 60, 3)

> test_list
=> [0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57]

> test_list[4:7]
``````

What is the result? `[12, 15, 18]`. Because `12` is the fifth element of the `test_list`

#3

Thanks for the help!

#4

Your’re welcome

#5

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