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| Date | Thu, 25 Jul 2013 06:47:08 -0700 |
| From | Ethan Furman <ethan@stoneleaf.us> |
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| Subject | Re: Python 3: dict & dict.keys() |
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On 07/24/2013 11:01 PM, alex23 wrote: > On 25/07/2013 4:31 AM, Ethan Furman wrote: >> 2) Hopefully learn something about when a view is useful. > > I haven't seeen this mentioned - forgive me if it's a repeat - but views are constant references to whichever set they > represent. > > Python 2.7: > >>>> dd = dict(a=1,b=2,c=3) >>>> keys = dd.keys() >>>> 'a' in keys > True >>>> dd['d'] = 4 >>>> 'd' in keys > False > > Python 3.3: >>>> dd = dict(a=1,b=2,c=3) >>>> keys = dd.keys() >>>> 'a' in keys > True >>>> dd['d'] = 4 >>>> 'd' in keys > True > > If part of my code is only interested in what keys or values are present, it doesn't need to be given a reference to the > full dictionary, just to whichever view it cares about. In these cases why is a view better than just using the dict? Is it a safety so the you don't accidentally modify the dict? -- ~Ethan~
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Re: Python 3: dict & dict.keys() Ethan Furman <ethan@stoneleaf.us> - 2013-07-24 11:31 -0700
Re: Python 3: dict & dict.keys() alex23 <wuwei23@gmail.com> - 2013-07-25 16:01 +1000
Re: Python 3: dict & dict.keys() Ethan Furman <ethan@stoneleaf.us> - 2013-07-25 06:47 -0700
Re: Python 3: dict & dict.keys() Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-07-25 07:04 +0000
Re: Python 3: dict & dict.keys() Chris Angelico <rosuav@gmail.com> - 2013-07-25 18:02 +1000
Re: Python 3: dict & dict.keys() Peter Otten <__peter__@web.de> - 2013-07-25 10:13 +0200
Re: Python 3: dict & dict.keys() Ian Kelly <ian.g.kelly@gmail.com> - 2013-07-25 09:53 -0600
Re: Python 3: dict & dict.keys() Peter Otten <__peter__@web.de> - 2013-07-25 18:25 +0200
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