python reverse string ::-1 slice function equivalent

Question

I see how "String"[::-1] works to return "gnirtS"

But isn't this supposed to be compatible with the slice function?

"String"[slice(-1, 0, -1)] ?

This returns "gnirt"

`slice(-1, 0, -1)` is not equivalent to `[::-1]`. `slice(None, None, -1)` is. — DeepSpace, May 08 '21 at 19:53
Remember that the end of a slice is exclusive, so `slice(-1, 0, -1)` stops at index `1`, not `0`. — Barmar, May 08 '21 at 19:54

score 2 · Answer 1 · answered May 08 '21 at 19:55

2

slice(-1, 0, -1) is not equivalent to [::-1]. slice(None, None, -1) is.

class SliceNotationTranslator:
    def __getitem__(self, item):
        print(item)

s = SliceNotationTranslator()
s[::-1]

Outputs

slice(None, None, -1)

answered May 08 '21 at 19:55

DeepSpace

1 Answers1