[Nipy-devel] attributes error
Jonathan Taylor
jonathan.taylor at stanford.edu
Wed May 31 10:35:25 CDT 2006
hi brian,
i don't know if i am doing things right, but i can't get the
"implements=list,slice" to work properly.
jonathan
---------------
>>> from attributes import attribute
>>>
>>> class Test(object):
... class value(attribute): implements = list, slice
...
>>> a = Test()
>>> a.value = [slice(0,100,1)]*2
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "/home/jtaylo/code/nipy/lib/attributes.py", line 256, in set
self.validate(value)
File "/home/jtaylo/code/nipy/lib/attributes.py", line 211, in validate
if not self.isvalid(value): raise ProtocolOmission(
protocols.ProtocolOmission: attribute value implements (<type 'list'>,
<type 'slice'>), value [slice(0, 100, 1), slice(0, 100, 1)] of type
<type 'list'> does not implement: ('indices', 'start', 'step', 'stop',
'__cmp__')
>>> a.value = slice(0,100,1)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "/home/jtaylo/code/nipy/lib/attributes.py", line 256, in set
self.validate(value)
File "/home/jtaylo/code/nipy/lib/attributes.py", line 211, in validate
if not self.isvalid(value): raise ProtocolOmission(
protocols.ProtocolOmission: attribute value implements (<type 'list'>,
<type 'slice'>), value slice(0, 100, 1) of type <type 'slice'> does not
implement: ('__getslice__', 'pop', 'remove', '__rmul__', '__lt__',
'append', 'index', '__delslice__', '__getitem__', '__contains__',
'__len__', 'sort', '__ne__', 'extend', 'insert', '__iter__', '__add__',
'__gt__', '__eq__', 'reverse', 'count', '__delitem__', '__reversed__',
'__imul__', '__setslice__', '__setitem__', '__iadd__', '__le__',
'__mul__', '__ge__')
>>>
---------------------------------------
Brian Hawthorne wrote:
> jonathan,
> for the declaration of the slice attribute, set implements=list,slice.
>
> regarding modifying the value of slice, i highly recommend simply
> constructing
> a new SliceIteratorNext with the new slice value instead of modifying
> the existing one.
> in general, it's a good idea to modify objects as little as possible
> and favor copying.
> a good bit of the work i've done one the codebase so far is oriented
> toward shifting from a modify to a copy pattern. modification can
> generate hidden dependencies which are
> hard to debug and untangle, making the code harder to scale and maintain.
>
> -brian
>
>
> On 5/28/06, *Jonathan Taylor* <jonathan.taylor at stanford.edu
> <mailto:jonathan.taylor at stanford.edu>> wrote:
>
> I wanted to change a read-only attribute (the slice attribute of
> SliceIteratorNext) to
> not read-only but "untyped". I changed "readonly" to "attribute"
> and got
> the following message:
>
> --------------
> Traceback (most recent call last):
> File "run.py", line 173, in ?
> FIACrun(subj=subj, run=run)
> File "run.py", line 134, in FIACrun
> OLS.fit ()
> File
> "/home/jtaylo/python/lib/python2.4/site-packages/neuroimaging/fmri/fmristat/__init__.py",
> line 107, in fit
> LinearModelIterator.fit(self, **keywords)
> File
> "/home/jtaylo/python/lib/python2.4/site-packages/neuroimaging/statistics/regression.py",
>
> line 48, in fit
> output.next(data=out)
> File
> "/home/jtaylo/python/lib/python2.4/site-packages/neuroimaging/fmri/regression.py",
> line 40, in next
> value.slice = value.slice[1]
> File "/home/jtaylo/python/lib/python2.4/site-packages/attributes.py",
> line 256, in set
> self.validate(value)
> File "/home/jtaylo/python/lib/python2.4/site-packages/attributes.py",
> line 211, in validate
> if not self.isvalid(value): raise ProtocolOmission(
> protocols.ProtocolOmission : attribute slice implements ([slice(0,
> 191,
> 1), slice(0, 1, 1)],), value slice(0, 1, 1) of type <type 'slice'>
> does
> not implement: ('__getslice__', 'pop', 'remove', '__rmul__', '__lt__',
> 'append', 'index', '__delslice__', '__getitem__', '__contains__',
> '__len__', 'sort', '__ne__', 'extend', 'insert', '__iter__',
> '__add__',
> '__gt__', '__eq__', 'reverse', 'count', '__delitem__', '__reversed__',
> '__imul__', '__setslice__', '__setitem__', '__iadd__', '__le__',
> '__mul__', '__ge__')
>
> ---------------------------
>
> I am not sure how to get this to work. I want it to behave like a
> slice or a list of slices.
>
> There is a very good example when you want to be able to change
> its value later: when the "iterator" driving the voxelwise
> analysis comes from an fMRI image, it spits out
> slices of time series, but if you want to output slices of floats
> (i.e. a 3d image of means), you want to ignore the first part of
> this (python) slice but you can still use the same
> "SliceIteratorNext" instance to drive the next method of the
> images....
>
> Thanks,
>
> Jonathan
>
> --
> ------------------------------------------------------------------------
> I'm part of the Team in Training: please support our efforts for the
> Leukemia and Lymphoma Society!
>
> http://www.active.com/donate/tntsvmb/tntsvmbJTaylor
>
> GO TEAM !!!
>
> ------------------------------------------------------------------------
>
> Jonathan Taylor Tel: 650.723.9230
> Dept. of Statistics Fax: 650.725.8977
> Sequoia Hall, 137
> www-stat.stanford.edu/~jtaylo <http://www-stat.stanford.edu/%7Ejtaylo>
> 390 Serra Mall
> Stanford, CA 94305
>
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--
------------------------------------------------------------------------
I'm part of the Team in Training: please support our efforts for the
Leukemia and Lymphoma Society!
http://www.active.com/donate/tntsvmb/tntsvmbJTaylor
GO TEAM !!!
------------------------------------------------------------------------
Jonathan Taylor Tel: 650.723.9230
Dept. of Statistics Fax: 650.725.8977
Sequoia Hall, 137 www-stat.stanford.edu/~jtaylo
390 Serra Mall
Stanford, CA 94305
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