Newbie question about numpy
Hi I'm new to python and have just been taking a look at what it has to offer. I noted the lack of matrices so installed numpy I know the documentation is chargable so wanted a quick play to see if I should buy it However _ from numpy import * a = array([[1,2,3],[4,5,6],[1,2,3]]) b = array([[1,3,6],[2,5,1],[1,1,1]]) print 'a = \n',a,"\n" print 'b = \n',b,"\n" print 'a has shape ', a.shape print 'b has shape ', b.shape, "\n" print "a * b is \n", a * b _ Gives me _ a = [[1 2 3] [4 5 6] [1 2 3]] b = [[1 3 6] [2 5 1] [1 1 1]] a has shape (3, 3) b has shape (3, 3) a * b is [[ 1 6 18] [ 8 25 6] [ 1 2 3]] _ I know its a long time since my degree but that's not matrix multiplication is it ? TIA Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie question about numpy
On Thu, 24 Aug 2006 17:23:49 GMT, Dennis Lee Bieber <[EMAIL PROTECTED]> wrote: >On Thu, 24 Aug 2006 16:38:45 +0100, Paul Johnston ><[EMAIL PROTECTED]> declaimed the following in >comp.lang.python: > >> I know its a long time since my degree but that's not matrix >> multiplication is it ? > > Define "matrix multiplication"... > > What you see appears to be multiplication of corresponding elements. > > Were you expecting a dot product, or a cross product, or something >else? > That as explained in http://people.hofstra.edu/faculty/stefan_Waner/RealWorld/tutorialsf1/frames3_2.html As I say its been a long time :-) Thanks to everyone for the help. Paul -- http://mail.python.org/mailman/listinfo/python-list
Unicode characters
Hi I have a string which I convert into a list then read through it printing its glyph and numeric representation #-*- coding: utf-8 -*- thestring = "abcd" thelist = list(thestring) for c in thelist: print c, print ord(c) Works fine for latin characters but when I put in a unicode character a two byte character gives me two characters. For example an arabic alef returns * 216 * 167 ( the first asterix is the empty set symbol the second a double "s") Putting in sequential characters i.e. alef, beh, teh mabuta, gives me sequential listings i.e. 216 167 216 168 216 169 So it is reading the correct details. Is there anyway to get the c in the for loop to recognise it is reading a multiple byte character. I have followed the info in PEP 0263 and am using Python 2.4.3 Build 12 on a Windows box within Eclipse 3.2.0 and Python plugins 1.2.2 Cheers Paul -- http://mail.python.org/mailman/listinfo/python-list
Detecting Updates on Arbitrary Objects
Hi,
I would like to be able to install a code hook to detect updates on
arbitrary objects. To give some background, I'm writing a web widget
library, that uses request-local storage. If there's a mutable object
on a widget (a dict is common), I'd like any attempts to update the
dict to cause the dict to be cloned into request-local storage and the
update applied.
Now, I did have this working quite nicely for dict and list instances,
by subclassing dict and list, and overriding the write methods (or
most of them - __setitem__, __delitem__, append, etc.) When the dict/
list is added to the widget, it's replaced with a clone, using the
DictProxy/ListProxy subclass. (I realise Proxy may have been slightly
inaccurate as a name) However, sometimes a user needs to use a list-
like object that isn't a list, and this approach breaks down.
So, I think I need to do a real object proxy - a class that defers
almost all attributes to an inner instance that it stores, but
overrides a few. The following is my initial attempt, which almost
works, but I think there must be a better way. In particular, needing
to explicitly override __iter__ and __eq__ spells trouble - what about
__ne__, __gt__, etc. Also, is there a way to catch just any change,
rather than trying to know all the change methods. A way to do this
for arbitrary objects (not just dicts and lists) would be good too.
Any hints, tips, or pointers to docs online?
Thanks,
Paul
class GenericProxy(object):
def __init__(self, obj):
self._obj = obj
def __getattr__(self, a):
return getattr(self._obj, a)
def __iter__(self):
return self._obj.__iter__()
def __eq__(self, x):
return self._obj.__eq__(x)
__setitem__ = _catch_modify('__setitem__')
__delitem__ = _catch_modify('__delitem__')
append = _catch_modify('append')
insert = _catch_modify('insert')
--
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jpeg package
Hi, I've used the jpeg library on PyPI in the past and it's been great: http://pypi.python.org/pypi/jpeg/0.1.4 However, the library home page is now unaccessible. I can't even find the library on archive.org. Any idea how I can get it? http://www.emilas.com/jpeg/ Thanks, Paul -- http://mail.python.org/mailman/listinfo/python-list
class or instance method
Hi, I would like to have a method that is both a classmethod and an instancemethod. So: class MyClass(object): @class_or_instance def myfunc(cls_or_self): pass The semantics I'd like are: When you call MyClass.myfunc, it gets passed a class When you call MyClass().myfunc, it gets passed an instance I'm sure I've seen some code to do this somewhere, but I can't find it now. Any help appreciated. Paul -- http://mail.python.org/mailman/listinfo/python-list
Re: class or instance method
Hi, > class class_or_instance(object): > def __init__(self, fn): ... This works a treat, thank-you. Paul -- http://mail.python.org/mailman/listinfo/python-list
Determining __name__ from the code that called a function
Hi, In ToscaWidgets 2 experimental, when defining resources you often do something like this: CSSLink(modname=__name__, filename='static/mycss.css') Now, what I'd like to do is make the "modname=__name__" optional, to make code more concise. I figure there must be some way (using inspect or something) to determine what __name__ would be in the code that just called my function. Couldn't immediately see how to do this - any suggestions? Thanks, Paul -- http://mail.python.org/mailman/listinfo/python-list
