Problem with Help when using numarray

Robert Kern rkern at ucsd.edu
Fri Sep 16 19:15:23 CEST 2005


Colin J. Williams wrote:
> Python advertises some basic service:
> 
> C:\Python24>python
> Python 2.4.1 (#65, Mar 30 2005, 09:13:57) [MSC v.1310 32 bit (Intel)] on 
> win32
> Type "help", "copyright", "credits" or "license" for more information.
>  >>>
> 
> With numarray, help gives unhelpful responses:
> 
> import numarray.numarraycore as _n
> c= _n.array((1, 2))
> print 'rank Value:', c.rank
> print 'c.rank Help:', help(c.rank)
> 
> Results:
> rank Value: 1
> c.rank Help:Help on int object:
> 
> class int(object)
>   |  int(x[, base]) -> integer
>   |
>   |  Convert a string or number to an integer, if possible.  A floating 
> point
>   |  argument will be truncated towards zero (this does not include a 
> .................  etc etc.

c.rank is an integer, not a method. It doesn't have a docstring. It
can't have a docstring.

> Another example:
> 
>  >>> help(c.copy)
> <bound method NumArray.copy of array([1, 2])>
>  >>> help(c.copy)
> Traceback (most recent call last):
>    File "<interactive input>", line 1, in ?
>    File "site.py", line 328, in __call__
>      return pydoc.help(*args, **kwds)
>    File "C:\Python24\lib\pydoc.py", line 1647, in __call__
>      self.help(request)
>    File "C:\Python24\lib\pydoc.py", line 1691, in help
>      else: doc(request, 'Help on %s:')
>    File "C:\Python24\lib\pydoc.py", line 1475, in doc
>      pager(title % desc + '\n\n' + text.document(object, name))
>    File "C:\Python24\lib\pydoc.py", line 297, in document
>      if inspect.isroutine(object): return self.docroutine(*args)
>    File "C:\Python24\lib\pydoc.py", line 1226, in docroutine
>      if object.im_self:
>    File "C:\Python24\Lib\site-packages\numarray\generic.py", line 537, 
> in __nonzero__
>      raise RuntimeError("An array doesn't make sense as a truth value. 
> Use any(a) or all(a).")
> RuntimeError: An array doesn't make sense as a truth value.  Use any(a) 
> or all(a).
>  >>>

c.copy.im_self is c . pydoc is trying to use it as a truth value (I'm
not sure why, you'll have to take it up with pydoc, not numarray), but
numarray has made a decision not to implement __nonzero__.

-- 
Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
 Are the graves of dreams allowed to die."
  -- Richard Harter




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