[Tutor] On slicing

george fragos fragos.george at gmail.com
Thu Sep 17 23:27:56 CEST 2009


2009/9/17 Rich Lovely <roadierich at googlemail.com>:
> 2009/9/17 george fragos <fragos.george at gmail.com>:
>>  If numbers=[1,2,3,4,5,6,7,8,9,10] and since "...any time the
>> leftmost index in a slice comes later in the seqence than the second
>> one... the result is always an empty sequence", why the slice
>> numbers[10:0:-2] produces the sequence [10,8,6,4,2] but not the
>> sequence []?
>> _______________________________________________
>> Tutor maillist  -  Tutor at python.org
>> To unsubscribe or change subscription options:
>> http://mail.python.org/mailman/listinfo/tutor
>>
>
> There should be a caveat to that:  Unless the third index (step) is negative.
>
> The first value is start, the second stop, and the third step.  What
> you are saying with numbers[10,0,-2], is start at 10 (facing towards
> the end of the sequence), keep going until you get to 0, taking two
> steps backwards each time.
>
> I hope that clears things up a little..
>
> --
> Rich "Roadie Rich" Lovely
>
> There are 10 types of people in the world: those who know binary,
> those who do not, and those who are off by one.
>

Thanx for your reply...!
By the way, I'd like to say hallo to the List and state that I'm just
starting with Python...!

George Fragos


More information about the Tutor mailing list