[SciPy-user] Question about trick index functions.
hgamboa at gmail.com
Thu Jan 5 21:25:58 CST 2006
I got the idea, and since I'm still working my transition from matlab
I thought that the c_ for one dimension would do a row vector, for
those quick matrix build ups like:
matrix([[2, 3, 4],
[3, 4, 5],
[4, 5, 6]])
that is even better than in matlab via the broadcasting functionality.
I thought that for using that kind of broadcasting I could use a very
quick code like:
Thanks for the quick answers.
On 1/6/06, Travis Oliphant <oliphant.travis at ieee.org> wrote:
> Hugo Gamboa wrote:
> >So what is the difference between r_ and c_ ?
> c_ is deprecated (it's there only for compatibility) :-)
> For 1-d arrays there was never any difference.
> For 2-d arrays c_ and r_ stacked along different dimensions.
> Now, the r_ constructor can stack along any dimension by using a string
> integer as the last element, but note this has the same limitation as
> concatenate: the arrays stacked together must actually have the
> dimension to stack along....
> Compare the output of
> a = arange(6).reshape(2,3)
> c_[a,a] # not recommended for use anymore...
> The real use of r_ is to quickly concatenate arrays together to build
> up complicated arrays. It was developed when I was using SciPy to teach
> a signal processing course and the student lab-manuals had Matlab
> exercises where they used matlab to build up compilcated arrays quickly
> using bracket notation:
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