[Tutor] Counting a string backwards

Alan Gauld alan.gauld at yahoo.co.uk
Sun May 28 19:19:40 EDT 2017

On 28/05/17 18:58, C W wrote:

> Now if I do case 2,
>> print(great[-3:-1])
>> me
> Where did the exclamation mark go in case 2?
> I was told the count begins at zero, that's true going forward, but not
> backwards.

Its not about where the count starts its about where it finishes.
It finishes 1 item before the second index. so in this case
you get the items at -3 and -2.

If you specify a third parameter you can change the
direction of the count thus:

>>> great[-1:-3:-1]

So now you get the characters at -1 and -2 (ie in reverse order)

If you want them in original order starting at -3 just omit
the -1:

>>> great[-3:]


Alan G
Author of the Learn to Program web site
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