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Groups > comp.lang.python > #102840

Re: Storing a big amount of path names

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On 2016-02-12 00:31, Paulo da Silva wrote:
> Hi!
>
> What is the best (shortest memory usage) way to store lots of pathnames
> in memory where:
>
> 1. Path names are pathname=(dirname,filename)
> 2. There many different dirnames but much less than pathnames
> 3. dirnames have in general many chars
>
> The idea is to share the common dirnames.
>
> More realistically not only the pathnames are stored but objects each
> object being a MyFile containing
> self.name - <base name>
> getPathname(self) - <full pathname>
> other stuff
>
> class MyFile:
>
>    __allfiles=[]
>
>    def __init__(self,dirname,filename):
>      self.dirname=dirname  # But I want to share this with other files
>      self.name=filename
>      MyFile.__allfiles.append(self)
>      ...
>
>    def getPathname(self):
>      return os.path.join(self.dirname,self.name)
>
>    ...
>
Apart from all of the other answers that have been given:

 >>> p1 = 'foo/bar'
 >>> p2 = 'foo/bar'
 >>> id(p1), id(p2)
(982008930176, 982008930120)
 >>> d = {}
 >>> id(d.setdefault(p1, p1))
982008930176
 >>> id(d.setdefault(p2, p2))
982008930176

The dict maps equal strings (dirnames) to the same string, so you won't 
have multiple copies.

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Storing a big amount of path names Paulo da Silva <p_s_d_a_s_i_l_v_a_ns@netcabo.pt> - 2016-02-12 00:31 +0000
  Re: Storing a big amount of path names Chris Angelico <rosuav@gmail.com> - 2016-02-12 11:39 +1100
  Re: Storing a big amount of path names Ben Finney <ben+python@benfinney.id.au> - 2016-02-12 11:44 +1100
  Re: Storing a big amount of path names Tim Chase <python.list@tim.thechases.com> - 2016-02-11 19:13 -0600
    Re: Storing a big amount of path names Rob Gaddi <rgaddi@highlandtechnology.invalid> - 2016-02-12 02:17 +0000
  Re: Storing a big amount of path names MRAB <python@mrabarnett.plus.com> - 2016-02-12 03:13 +0000
  Re: Storing a big amount of path names Chris Angelico <rosuav@gmail.com> - 2016-02-12 14:49 +1100
    Re: Storing a big amount of path names Paulo da Silva <p_s_d_a_s_i_l_v_a_ns@netcabo.pt> - 2016-02-12 04:15 +0000
      Re: Storing a big amount of path names Chris Angelico <rosuav@gmail.com> - 2016-02-12 15:23 +1100
        Re: Storing a big amount of path names Paulo da Silva <p_s_d_a_s_i_l_v_a_ns@netcabo.pt> - 2016-02-12 04:45 +0000
          Re: Storing a big amount of path names Chris Angelico <rosuav@gmail.com> - 2016-02-12 16:02 +1100
            Re: Storing a big amount of path names Paulo da Silva <p_s_d_a_s_i_l_v_a_ns@netcabo.pt> - 2016-02-12 05:49 +0000
            Re: Storing a big amount of path names Steven D'Aprano <steve@pearwood.info> - 2016-02-12 16:51 +1100
        Re: Storing a big amount of path names Rob Gaddi <rgaddi@highlandtechnology.invalid> - 2016-02-12 17:05 +0000
          Re: Storing a big amount of path names Chris Angelico <rosuav@gmail.com> - 2016-02-13 04:18 +1100
          Re: Storing a big amount of path names Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-02-12 21:37 +0000
          Re: Storing a big amount of path names Ben Finney <ben+python@benfinney.id.au> - 2016-02-13 08:49 +1100
          Re: Storing a big amount of path names Matt Wheeler <funkyhat@gmail.com> - 2016-02-12 23:31 +0000
            Re: Storing a big amount of path names mkondrashin@gmail.com - 2016-02-13 12:19 -0800
  Re: Storing a big amount of path names srinivas devaki <mr.eightnoteight@gmail.com> - 2016-02-12 11:46 +0530

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