Slicing history?

Jon Clements joncle at
Sun Nov 15 20:01:49 CET 2009

On Nov 15, 6:50 pm, a... at (Aahz) wrote:
> Anyone remember or know why Python slices function like half-open
> intervals?  I find it incredibly convenient myself, but an acquaintance
> familiar with other programming languages thinks it's bizarre and I'm
> wondering how it happened.
> --
> Aahz (a... at           <*>
> [on old computer technologies and programmers]  "Fancy tail fins on a
> brand new '59 Cadillac didn't mean throwing out a whole generation of
> mechanics who started with model As."  --Andrew Dalke

Good ol' zero based indexing. It makes a lot more sense that range(len
(my_list)) returns 'n' values which are valid indicies, otherwise
they'd be a lot of IndexError's being raised.

Besides, when you really want the full range (a corner case), it's a
lot easier to do a +1, than to force people to write -1 for the vast
majority of cases.


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