Groups > comp.lang.python > #101979

Re: importing: what does "from" do?

From	Ian Kelly <ian.g.kelly@gmail.com>
Newsgroups	comp.lang.python
Subject	Re: importing: what does "from" do?
Date	2016-01-21 08:59 -0700
Message-ID	<mailman.153.1453392020.15297.python-list@python.org> (permalink)
References	<n7qpel$a3j$1@dont-email.me> <mailman.151.1453387942.15297.python-list@python.org> <n7qsgd$a3j$2@dont-email.me>

Show all headers | View raw

On Thu, Jan 21, 2016 at 8:12 AM, Charles T. Smith
<cts.private.yahoo@gmail.com> wrote:
>>> would you explain to me why I get this:
>>>
>>>   (PDB)hexdump(msg)
>>> *** NameError: name 'hexdump' is not defined
>>
>> Probably because the name 'hexdump' is not defined.
>
>
> If indeed it's not defined, then I wouldn't think there'd be a
> problem importing the module that defines it.

What happens if you just do 'import utilities'. Can you then call
utilities.hexdump? Can you see anything in the utilities module?

>  'hexdump': <module 'hexdump' from '/home/user/hexdump.pyc'>,
>  'int.hexdump': None,
>
>
> But I suspect the first, at any rate, was loaded because of this in
> my ~/.pdbrc:
>
>   from hexdump import hexdump
>
> which wouldn't interfere when running without the debugger (that module
> in my sys.path but nowhere near my project)
>
>
> I have this in my project:
>
>   int/__init__.py
>
> But:
>
>   $ ls int/hexdump*
>   ls: cannot access int/hexdump*: No such file or directory
>
> So I don't really understand "int.hexdump".

The value of None in sys.modules caches a relative import miss. All it
means is that at some point something in the 'int' package tried to do
a relative import of the hexdump module and failed (presumably because
it doesn't exist).

Side observation: 'int' is a bad name for a package, because it will
shadow the name of the 'int' built-in.

Thread

importing: what does "from" do? "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2016-01-21 14:20 +0000
  Re: importing: what does "from" do? Ian Kelly <ian.g.kelly@gmail.com> - 2016-01-21 07:52 -0700
    Re: importing: what does "from" do? "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2016-01-21 15:12 +0000
      Re: importing: what does "from" do? Ian Kelly <ian.g.kelly@gmail.com> - 2016-01-21 08:59 -0700
        Re: importing: what does "from" do? "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2016-01-21 16:30 +0000
          Re: importing: what does "from" do? "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2016-01-21 16:41 +0000
      Re: importing: what does "from" do? Steven D'Aprano <steve@pearwood.info> - 2016-01-22 03:22 +1100
  Re: importing: what does "from" do? John Gordon <gordon@panix.com> - 2016-01-21 15:31 +0000
    Re: importing: what does "from" do? "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2016-01-21 15:37 +0000
      Re: importing: what does "from" do? John Gordon <gordon@panix.com> - 2016-01-21 15:44 +0000
        Re: importing: what does "from" do? "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2016-01-21 15:46 +0000
          Re: importing: what does "from" do? John Gordon <gordon@panix.com> - 2016-01-21 15:59 +0000
        Re: importing: what does "from" do? "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2016-01-21 15:53 +0000
          Re: importing: what does "from" do? Steven D'Aprano <steve@pearwood.info> - 2016-01-22 03:28 +1100
  Re: importing: what does "from" do? Rustom Mody <rustompmody@gmail.com> - 2016-01-21 23:03 -0800
    Refactoring in a large code base (was: importing: what does "from" do?) Ben Finney <ben+python@benfinney.id.au> - 2016-01-22 18:54 +1100
      Re: Refactoring in a large code base Marko Rauhamaa <marko@pacujo.net> - 2016-01-22 10:29 +0200
        Re: Refactoring in a large code base Rustom Mody <rustompmody@gmail.com> - 2016-01-22 01:21 -0800
          Re: Refactoring in a large code base Marko Rauhamaa <marko@pacujo.net> - 2016-01-22 12:19 +0200
            Re: Refactoring in a large code base Chris Angelico <rosuav@gmail.com> - 2016-01-22 22:19 +1100
              Re: Refactoring in a large code base Marko Rauhamaa <marko@pacujo.net> - 2016-01-22 13:54 +0200
                Re: Refactoring in a large code base Chris Angelico <rosuav@gmail.com> - 2016-01-22 23:28 +1100
                Re: Refactoring in a large code base Marko Rauhamaa <marko@pacujo.net> - 2016-01-22 15:00 +0200
                Re: Refactoring in a large code base Chris Angelico <rosuav@gmail.com> - 2016-01-23 00:26 +1100
                Re: Refactoring in a large code base Marko Rauhamaa <marko@pacujo.net> - 2016-01-22 15:48 +0200
                Re: Refactoring in a large code base Chris Angelico <rosuav@gmail.com> - 2016-01-23 01:09 +1100
              Re: Refactoring in a large code base Rustom Mody <rustompmody@gmail.com> - 2016-01-22 04:04 -0800
                Re: Refactoring in a large code base Marko Rauhamaa <marko@pacujo.net> - 2016-01-22 14:21 +0200
                Re: Refactoring in a large code base Thomas Mellman <tmellman@web.de> - 2016-01-22 12:27 +0000
                Re: Refactoring in a large code base Chris Angelico <rosuav@gmail.com> - 2016-01-22 23:34 +1100
                Re: Refactoring in a large code base Rustom Mody <rustompmody@gmail.com> - 2016-01-22 05:30 -0800
                Re: Refactoring in a large code base Marko Rauhamaa <marko@pacujo.net> - 2016-01-22 15:43 +0200
                Re: Refactoring in a large code base Rustom Mody <rustompmody@gmail.com> - 2016-01-22 05:58 -0800
                Re: Refactoring in a large code base Chris Angelico <rosuav@gmail.com> - 2016-01-23 01:08 +1100
            Re: Refactoring in a large code base "Charles T. Smith" <cts.private.yahoo@gmail.com> - 2016-01-22 11:45 +0000

csiph-web