# [SciPy-dev] draft: NumPy User Guide introduction

Andrew Hawryluk HAWRYLA@novachem....
Thu Aug 20 18:09:55 CDT 2009

```> -----Original Message-----
> From: scipy-dev-bounces@scipy.org [mailto:scipy-dev-bounces@scipy.org]
> On Behalf Of Stéfan van der Walt
> Sent: 20 Aug 2009 4:34 PM
> To: SciPy Developers List
> Subject: Re: [SciPy-dev] draft: NumPy User Guide introduction
>
> Hi Andrew
>
> 2009/8/20 Andrew Hawryluk <HAWRYLA@novachem.com>:
> > I have posted a first draft of a NumPy User Guide introduction.
> > Hopefully it is both useful and factually correct, but please jump in
> > where you see room for improvement.
>
> Thanks for taking the time to work on this!

You're welcome!

>
> The array multiplication example is a bit confusing, unless you read
> ahead to figure out that you are talking about 1-dimension arrays or
> vectors. On the Python side there is a small typo (len instead of
> len(a)), and on the C++ side the size is not defined.

Good point. I removed the length comparison for consistency and brevity.

> The term universal function should be explained: a function that
> operates on a single element of an array at a time, applied to all
> elements.

Done. Thanks!

> I think it's best to encourage people to use np.* functions, instead of
> arr.* methods (maybe others differ with me on this point?).
>
> This is a good start, and I think it can be expanded with some more
> examples.  I wrote an intro while working on the docs last year:
>
> http://mentat.za.net/numpy/intro/intro.html

That looks great. I will take a closer look.

> Unfortunately, numpy arrays are not easy to teach in one page, so these
> introductions tend to grow!

Indeed. A couple of brief examples would be very examples, but I think the bulk of the 'feature tour' should stay in the NumPy basics section, which is nicely organized and could be expanded as needed.

Thanks,
Andrew
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