[IPython-User] question about extensions

[Michael Kuhlen]

You're the best!

Thanks for patiently explaining the basics.

Mike

On Wed, Oct 17, 2012 at 11:52 AM, MinRK <benjaminrk@gmail.com> wrote:
>
>
> On Wed, Oct 17, 2012 at 11:38 AM, Michael Kuhlen <kuhlen@gmail.com> wrote:
>>
>> Hi there
>>
>> A question about IPython extensions. From reading the documentation it
>> looks like extension are meant to modify the behaviour of the shell,
>> and so my question might not make any sense, but let me ask anyway. Is
>> there some way to use extensions inside an externally defined
>> function?
>>
>> More specifically, I've been using the ipython-physics
>> (https://bitbucket.org/birkenfeld/ipython-physics) extension to handle
>> physical quantities with units. This works great in the IPython shell
>> and in notebooks, but it doesn't seem to work when I try to use it
>> inside externally defined functions. Here's what I mean:
>>
>> In [1]: %load_ext physics
>> Unit calculation and physics extensions activated.
>>
>> In [2]: print Q('1 hplanck').base
>> 6.6260696e-34 m^2*kg/s
>>
>> In [3]: def test():
>>    ...:     print Q('1 hplanck').base
>>    ...:
>>
>> In [4]: test()
>> 6.6260696e-34 m^2*kg/s
>>
>> In [5]: !cat test.py
>> def test():
>>     print Q('1 hplanck').base
>>
>> In [6]: import test as t
>>
>> In [7]: t.test()
>>
>> ---------------------------------------------------------------------------
>> NameError                                 Traceback (most recent call
>> last)
>> <ipython-input-6-f69a6e70fa4a> in <module>()
>> ----> 1 t.test()
>>
>> /home/mqk/test.py in test()
>>       1 def test():
>> ----> 2     print Q('1 hplanck').base
>>
>> NameError: global name 'Q' is not defined
>>
>>
>>
>> Perhaps this is unavoidable, but I'd love to find a way to use
>> physical quantities also inside externally defined functions.
>
>
> extensions are just modules on a special path.  They do not (generally)
> affect anything other than the user namespace and IPython itself.
>
> To get a name from an extension, you treat it just like any other module (at
> least after it has been loaded):
>
> # load the extension first, so that the 'physics' module exists
> %load_ext physics
>
> # then its names become importable:
> from physics import Q
>
> -MinRK
>
>>
>> Any insights?
>>
>> Thanks,
>>
>> Mike
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>
>
>
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-- 
*********************************************************************
*                                                                   *
*  Dr. Michael Kuhlen              Theoretical Astrophysics Center  *
*  email: mqk@astro.berkeley.edu   UC Berkeley                      *
*  cell phone: (831) 588-1468      B-116 Hearst Field Annex # 3411  *
*  skype username: mikekuhlen      Berkeley, CA 94720               *
*                                                                   *
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