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Re: How is max supposed to work, especially key.

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On Thu, Dec 4, 2014 at 9:09 PM, Albert van der Horst
<albert@spenarnc.xs4all.nl> wrote:
>>If there is more than one item with the maximum calculated the first is
>>given, so for your attempt
>>
>>max(xrange(100,200), key=lambda i: i%17==0 )
>
>>
>>the values False, False, True, False, ... are calculated and because
>>
>>>>> True > False
>>True
>>
>>the first one with a True result is returned.
>>
>
> So in that case max doesn't return the maximum (True), but instead
> something else.
>
> Useful as that function may be, it shouldn't have been called max.
>
> I don't blame myself for being misled.

If lots of them are equally the largest, by whatever definition of
largest you have, it has to do one of three things:

1) Raise an exception
2) Return multiple items (either as a tuple, or a generator, or something)
3) Pick one of them and return it.

Python's max() does the third, and for the picking part, uses the
first one it comes across - a decent way to do it.

If there's no clear maximum, it can't do any better than that. It's
still returning something for which there is no greater.

ChrisA

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Thread

How is max supposed to work, especially key. albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-11-27 17:34 +0000
  Re: How is max supposed to work, especially key. Peter Otten <__peter__@web.de> - 2014-11-27 19:01 +0100
    Re: How is max supposed to work, especially key. albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-12-04 10:09 +0000
      Re: How is max supposed to work, especially key. Chris Angelico <rosuav@gmail.com> - 2014-12-04 21:18 +1100
        Re: How is max supposed to work, especially key. albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-12-04 10:35 +0000
          Re: How is max supposed to work, especially key. Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2014-12-04 12:51 +0200
          Re: How is max supposed to work, especially key. Peter Otten <__peter__@web.de> - 2014-12-04 12:31 +0100
          Re: How is max supposed to work, especially key. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-04 23:03 +1100
          Re: How is max supposed to work, especially key. Terry Reedy <tjreedy@udel.edu> - 2014-12-04 10:47 -0500
      Re: How is max supposed to work, especially key. Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2014-12-04 12:45 +0200
        Re: How is max supposed to work, especially key. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-04 22:55 +1100
          Re: How is max supposed to work, especially key. Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2014-12-04 14:58 +0200
      Re: How is max supposed to work, especially key. Peter Otten <__peter__@web.de> - 2014-12-04 12:24 +0100
      Re: How is max supposed to work, especially key. random832@fastmail.us - 2014-12-04 09:09 -0500

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