# [R] minimum from matrix

Gabor Csardi csardi at rmki.kfki.hu
Tue May 8 15:08:58 CEST 2007

```Corinna,

what is going on here? I've answered Oarabile's question, and then
you reply to me with this. I'm completely lost.

1. What is your question? Minimum of every row?
This was written in the original mail along with Oarabile's
question. Ok it wasn't rows but columns.
For rows it is apply(a, 1, min)
2. Why did you reply to my message?
3. And if you did so, why didn't you read the original message
4. Why did you add one row to the original matrix? Why is the new
matrix significantly different form the original one?

Gabor

On Tue, May 08, 2007 at 02:49:50PM +0200, Schmitt, Corinna wrote:
> Hallo,
>
>
> > a=rbind(a,1:4)
> > a
>      [,1] [,2] [,3] [,4]
> [1,]    0    1    2    0
> [2,]    2    3    0    4
> [3,]    0    0    3    0
> [4,]    0    3    5    0
> [5,]    1    2    3    4
>
> And how looks like the command for the minimum of the rows? The result should be minOfRows = 0 0 0 0 1
>
> Thanks,
> Corinna
>
>
>
>
>
> -----Ursprüngliche Nachricht-----
> Von: r-help-bounces at stat.math.ethz.ch [mailto:r-help-bounces at stat.math.ethz.ch] Im Auftrag von Gabor Csardi
> Gesendet: Dienstag, 8. Mai 2007 14:03
> An: oarabile at stams.strath.ac.uk
> Cc: r-help at stat.math.ethz.ch
> Betreff: Re: [R] minimum from matrix
>
> apply(a, 2, function(x) min(x[x!=0]) )
>
> should do it. Might need some improvement if all numbers in a column
> can be zero, try it.
>
> Gabor
>
> On Tue, May 08, 2007 at 09:50:43AM +0100, oarabile at stams.strath.ac.uk wrote:
> >
> >
> > I have a very large matrix with columns that have some of their
> > entries as zero
> >
> >
> > A small example if a=
> >
> >          [,1]  [,2]  [,3]  [,4]
> >      [,1] 0     2     0     0
> >      [,2] 1     3     0     3
> >      [,3] 2     0     3     5
> >      [,4] 0     4     0     0
> >
> > and what to get the minimum number from each column but that number
> > should not be zero. If I use apply (a,2,min) I will get a vector of
> > zeros as the minimum but what I want it for example from column 1 I
> > should get 1 i.e for all the matrix I should get a vector (1,2,3,3). I
> > wonder if someone can give an idea on how to go about it.
> >
> >
> > Oarabile
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > and provide commented, minimal, self-contained, reproducible code.
>
> --
> Csardi Gabor <csardi at rmki.kfki.hu>    MTA RMKI, ELTE TTK
>
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