# [R] Algebraic operation on the missing values

Petr Pikal petr.pikal at precheza.cz
Tue Aug 1 13:51:00 CEST 2006

```Hi

try to post some reproducible example and maybe somebody can help you
more. You need to handle missing values one way or another. Either
you can supply a value for it or you can get rid of them. If you used
it in computation, the result will be NA. At least I think so.

HTH
Petr

On 31 Jul 2006 at 14:37, Joanna Procelewska wrote:

Date sent:      	Mon, 31 Jul 2006 14:37:33 +0200 (CEST)
From:           	Joanna Procelewska <jprocelewska at yahoo.com>
To:             	r-help at stat.math.ethz.ch
Subject:        	Re: [R] Algebraic operation on the missing values

>
> The problem is I have to perform a forward selection on the set and in
> every step construct an orthonormal base for the subspace spanned on
> the selected vectors. This means that I can use only the "full"
> vectors for the constructing a base, or?
>
> Joanna
>
> --- Petr Pikal <petr.pikal at precheza.cz> schrieb:
>
> > Hi
> >
> > see
> > ?complete.cases and/or ?is.na for evaluating non missing entries.
> >
> > However in any operation in which you use NA value, result shall be
> > NA as you do not know what actually is NA.
> >
> > HTH
> > Petr
> >
> > > Hi all,
> > >
> > > I have a large set of descriptors, which are stored as the
> > > vectors, each one containing about 450 elements. Now I have to
> > > perform some algebraical operations on this set to eliminate the
> > > redundant ones. The problem is, that not all vales in the vectors
> > > are known. Are there any norm defined how should I process such
> > > vectors? Simple example: having two vectors:
> > >
> > > a      b
> > > 3      4
> > > 2      null
> > > 3      6
> > >
> > > I can imagine that a+b is [7 null 9]', but what about scalar
> > > product? Is it null or have it a value? I don't want to replace
> > > missing values with the concrete ones, but they significantly
> > > complicate my computations.
> > >
> > > Does anyone know whether there are any ways to solve this problem?
> > > Please share some experience. Really appreciate the help!
> > >
> > > Sincerely,
> > >
> > > Joanna
> > >
> > > ______________________________________________
> > > R-help at stat.math.ethz.ch mailing list
> > > https://stat.ethz.ch/mailman/listinfo/r-help
> > > http://www.R-project.org/posting-guide.html and provide commented,
> > > minimal, self-contained, reproducible code.
> >
> > Petr Pikal
> > petr.pikal at precheza.cz
> >
> >
>
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