[Numpy-discussion] transpose of a matrix should be another matrix

Chris Colbert sccolbert@gmail....
Tue Jul 7 00:46:01 CDT 2009


I should clarify, everything in python is an object. Even methods of
classes. The syntax to invoke a method is the method name followed by the
parenthese (). If you leave off the parentheses, python return the method
object. This can be useful if you want to pass the method to another
function or method which can then execute it.

They are no "pointers" in python so to speak. So passing a function or
method like this is the equivalent of a function pointer.

disclaimer: all arguments to functions are passed as pointers in C, but just
think of them as objects and you're better off.

Chris

On Tue, Jul 7, 2009 at 1:42 AM, Chris Colbert <sccolbert@gmail.com> wrote:

> you actually have to call the method as transpose(). What you requested was
> the actual method.
>
> >>> import numpy as np
> >>> a = np. matrix([[1,2,3],[4,5,6],[7,8,9]])
> >>> a
> matrix([[1, 2, 3],
>         [4, 5, 6],
>         [7, 8, 9]])
> >>> b = a.transpose()
> >>> b
> matrix([[1, 4, 7],
>         [2, 5, 8],
>         [3, 6, 9]])
>
> >>>
>
> On Tue, Jul 7, 2009 at 1:34 AM, Dr. Phillip M. Feldman <
> pfeldman@verizon.net> wrote:
>
>>
>> I'm using the Enthought Python Distribution. When I define a matrix and
>> transpose it, it appears that the result is no longer a matrix (see
>> below).
>> This is both surprising and disappointing.  Any suggestions will be
>> appreciated.
>>
>> In [16]: A=matrix([[1,2,3],[4,5,6],[7,8,9]])
>>
>> In [17]: B=A.transpose
>>
>> In [18]: A
>> Out[18]:
>> matrix([[1, 2, 3],
>>        [4, 5, 6],
>>        [7, 8, 9]])
>>
>> In [19]: B
>> Out[19]: <built-in method transpose of matrix object at 0x00CF2A30>
>> --
>> View this message in context:
>> http://www.nabble.com/transpose-of-a-matrix-should-be-another-matrix-tp24367402p24367402.html
>> Sent from the Numpy-discussion mailing list archive at Nabble.com.
>>
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>
>
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