Re: Make a unique filesystem path, without creating the file

From	Gregory Ewing <greg.ewing@canterbury.ac.nz>
Newsgroups	comp.lang.python
Subject	Re: Make a unique filesystem path, without creating the file
Date	2016-02-15 21:00 +1300
Message-ID	<didet7Ft04gU1@mid.individual.net> (permalink)
References	(1 earlier) <CAG93HwHjKewu-VHUUc1jL=cU-pDNxVtKxx6ORyr+mdLLSJx2TA@mail.gmail.com> <CAG93HwGRsvcc=9rGgOA=oi6C-3pTk-Kr3g4dxCN0ivvixTVPWw@mail.gmail.com> <mailman.121.1455494940.22075.python-list@python.org> <n9r8bk$evf$1@dont-email.me> <mailman.126.1455499198.22075.python-list@python.org>

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Ben Finney wrote:
> One valid filesystem path each time it's accessed. That is, behaviour
> equivalent to ‘tempfile.mktemp’.
> 
> My question is because the standard library clearly has this useful
> functionality implemented, but simultaneously warns strongly against its
> use.

But it *doesn't*, if your requirement is truly to not touch
the filesystem at all, because tempfile.mktemp() *reads* the
file system to make sure the name it's returning isn't
in use.

What's more, because you're *not* creating the file, mktemp()
would be within its rights to return the same file name the
second time you call it.

If you want something that really doesn't go near the file
system and/or is guaranteed to produce multiple different
non-existing file names, you'll have to write it yourself.

-- 
Greg

Thread

Re: Make a unique filesystem path, without creating the file Ben Finney <ben+python@benfinney.id.au> - 2016-02-15 11:08 +1100
  Re: Make a unique filesystem path, without creating the file Dan Sommers <dan@tombstonezero.net> - 2016-02-15 01:07 +0000
    Re: Make a unique filesystem path, without creating the file Ben Finney <ben+python@benfinney.id.au> - 2016-02-15 12:19 +1100
      Re: Make a unique filesystem path, without creating the file Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-02-15 15:54 +1100
        Re: Make a unique filesystem path, without creating the file Ben Finney <ben+python@benfinney.id.au> - 2016-02-15 16:25 +1100
        Re: Make a unique filesystem path, without creating the file Rick Johnson <rantingrickjohnson@gmail.com> - 2016-02-15 18:26 -0800
      Re: Make a unique filesystem path, without creating the file Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-02-15 21:00 +1300
        Re: Make a unique filesystem path, without creating the file Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-02-16 01:18 +0100
      Re: Make a unique filesystem path, without creating the file Grant Edwards <invalid@invalid.invalid> - 2016-02-15 15:49 +0000
  Re: Make a unique filesystem path, without creating the file Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-02-15 15:06 +1100
    Re: Make a unique filesystem path, without creating the file Ben Finney <ben+python@benfinney.id.au> - 2016-02-15 15:28 +1100
      Re: Make a unique filesystem path, without creating the file Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-02-15 21:11 +1300
      Re: Make a unique filesystem path, without creating the file Nobody <nobody@nowhere.invalid> - 2016-02-16 02:14 +0000
    Re: Make a unique filesystem path, without creating the file "Martin A. Brown" <martin@linux-ip.net> - 2016-02-14 20:48 -0800

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