# [Numpy-discussion] Vector magnitude?

Robert Dailey rcdailey@gmail....
Wed Sep 5 13:52:53 CDT 2007

```Oh I think I get it.

You mean the built-in len() function? This isn't what I am looking for.
len() returns the number of components in the vector (e.g. whether it is a
2D, 3D, etc vector). I found that magnitude can be calculated using hypot()
in the math module that comes with python. However, this method only appears
to work with 2D vectors. And yes, by magnitude I mean euclidean norm:

sqrt( x*x + y*y ) = magnitude (length) of a vector

On 9/5/07, Robert Dailey <rcdailey@gmail.com> wrote:
>
>
> I was not able to find len() in the numpy documentation at the following
> http://www.scipy.org/doc/numpy_api_docs/namespace_index.html
>
> Perhaps I'm looking in the wrong location?
>
> On 9/5/07, Matthieu Brucher <matthieu.brucher@gmail.com > wrote:
>
> >
> >
> > 2007/9/5, Robert Dailey < rcdailey@gmail.com>:
> > >
> > > Hi,
> > >
> > > I have two questions:
> > >
> > > 1) Is there any way in numpy to represent vectors? Currently I'm using
> > > 'array' for vectors.
> >
> >
> >
> > A vector is an array with one dimension, it's OK. You could use a matrix
> > of dimension 1xn or nx1 as well.
> >
> >
> > 2) Is there a way to calculate the magnitude (length) of a vector in
> > > numpy?
> >
> >
> > Yes, len(a)
> >
> > Matthieu
> >
> > _______________________________________________
> > Numpy-discussion mailing list
> > Numpy-discussion@scipy.org
> > http://projects.scipy.org/mailman/listinfo/numpy-discussion
> >
> >
>
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