On 05/08/2021 12.35, Jack Brandom wrote:
The FAQ at
https://docs.python.org/3/faq/programming.html#what-s-a-negative-index
makes me think that I can always replace negative indices with positive
ones --- even in slices, although the FAQ seems not to say anything
about slices.
With slices, it doesn't seem to always work. For instance, I can
reverse a "Jack" this way:
s = "Jack Brandom"
s[3 : -13 : -1]
'kcaJ'
I have no idea how to replace that -13 with a positive index. Is it
possible at all?
I don't think so, because the second number (in this case -13) is the
index before which you stop. For example:
>>> s
'Jack Brandom'
>>> s[3:0:-1]
'kca'
>>> s[3:1:-1]
'kc'
>>>
However, since you want to go through item 0 in the original string,
you don't need a number there at all:
>>> s[3::-1]
'kcaJ'
>>>
Or, it you want to be more explicit, you could separately grab the
substring and then reverse it:
>>> s[:4][::-1]
'kcaJ'
>>>
Does any of this help?
--
Michael F. Stemper
If it isn't running programs and it isn't fusing atoms, it's just
bending space.
--
https://mail.python.org/mailman/listinfo/python-list
