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Re: How to access the low digits of a list

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From Ian Kelly <ian.g.kelly@gmail.com>
Date Wed, 3 Jun 2015 16:36:21 -0600
Subject Re: How to access the low digits of a list
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On Wed, Jun 3, 2015 at 3:08 PM, Rustom Mody <rustompmody@gmail.com> wrote:
> On Tuesday, June 2, 2015 at 7:50:58 PM UTC+5:30, Ian wrote:
>> On Tue, Jun 2, 2015 at 6:35 AM, Rustom Mody  wrote:
>> > For that matter even this works
>> > But I am not sure whats happening or that I like it
>> >
>> >>>> [x[-2:]  for x in lines]
>> > ['12', '42', '49', '56', '25', '36', '49', '64', '81', '00']
>>
>> x[-2:] selects all items in the sequence with index i such that len(x)
>> - 2 <= i < len(x). For a sequence of length 2 or less, that's the
>> entire sequence.
>
> Thanks -- learn something
> So it means that indices can give indexerror; slices cannot?
> Seems fair enough put that way, but is visually counterintuitive

Yes. The rule I paraphrased above is stated at
https://docs.python.org/3/library/stdtypes.html#common-sequence-operations
-- scroll down to note 4. I don't know if there's anything that
clearly states that sequence slicing can't raise IndexError, but it is
at least implied by the above, and it is certainly true of all builtin
sequence types.

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Thread

How to access the low digits of a list fl <rxjwg98@gmail.com> - 2015-06-02 05:23 -0700
  Re: How to access the low digits of a list Joel Goldstick <joel.goldstick@gmail.com> - 2015-06-02 08:32 -0400
  Re: How to access the low digits of a list Frank Stutzman <stutzman@cat2.kjsl.com> - 2015-06-02 12:34 +0000
  Re: How to access the low digits of a list Rustom Mody <rustompmody@gmail.com> - 2015-06-02 05:35 -0700
    Re: How to access the low digits of a list Ian Kelly <ian.g.kelly@gmail.com> - 2015-06-02 08:19 -0600
      Re: How to access the low digits of a list Rustom Mody <rustompmody@gmail.com> - 2015-06-03 14:08 -0700
        Re: How to access the low digits of a list Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-06-03 22:41 +0100
        Re: How to access the low digits of a list Ian Kelly <ian.g.kelly@gmail.com> - 2015-06-03 16:36 -0600
        Re: How to access the low digits of a list Steven D'Aprano <steve@pearwood.info> - 2015-06-04 23:27 +1000
  Re: How to access the low digits of a list Steven D'Aprano <steve@pearwood.info> - 2015-06-03 01:11 +1000

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